diff --git a/CHANGELOG.md b/CHANGELOG.md
index c08696dfe..e8809ff04 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Hitobito PBS Changelog
 
+## unreleased
+
+*	  Das Feld "Geschwister in der Abteilung" wird neu von eingetragenen Geschwistern abgeleitet und pro Ebene bzw. pro Anlass berechnet und angezeigt. (hitobito#2147)
+
 ## Version 1.30
 
 *   Das Anwesenheiten-Tab bei Kursen im Status "Qualifikationen erfasst" und "Abgeschlossen" wird neu mit einem Ausrufezeichen markiert, wenn die Anwesenheiten noch gespeichert werden müssen. Merci @ewangler! (hitobito/hitobito_pbs#262)
diff --git a/app/decorators/pbs/person_decorator.rb b/app/decorators/pbs/person_decorator.rb
index 9b2479dd0..de24e5f10 100644
--- a/app/decorators/pbs/person_decorator.rb
+++ b/app/decorators/pbs/person_decorator.rb
@@ -20,10 +20,18 @@ def roles_grouped(scope:)
       end
     end
 
+    def siblings_in_context(context)
+      family_member_finder.family_members_in_context(context, kind: :sibling)
+    end
+
   end
 
   private
 
+    def family_member_finder 
+      @family_member_finder ||= Person::FamilyMemberFinder.new(self)
+    end
+
     def layer_group_ids
       @layer_group_ids ||= current_user&.layer_group_ids ||
         [current_service_token&.layer_group_id].compact.presence ||
diff --git a/app/domain/pbs/export/tabular/people/participation_row.rb b/app/domain/pbs/export/tabular/people/participation_row.rb
index 34152028e..653c1042e 100644
--- a/app/domain/pbs/export/tabular/people/participation_row.rb
+++ b/app/domain/pbs/export/tabular/people/participation_row.rb
@@ -15,6 +15,13 @@ def bsv_days
             participation.bsv_days || participation.event.bsv_days
           end
 
+          def has_siblings_in_event
+            event = participation.event
+
+            ::Person::FamilyMemberFinder.new(participation.person)
+                                        .family_members_in_context(event, kind: :sibling).any?
+          end
+          
         end
       end
     end
diff --git a/app/domain/pbs/export/tabular/people/participations_full.rb b/app/domain/pbs/export/tabular/people/participations_full.rb
index d51e647f7..5eda29b9b 100644
--- a/app/domain/pbs/export/tabular/people/participations_full.rb
+++ b/app/domain/pbs/export/tabular/people/participations_full.rb
@@ -13,12 +13,19 @@ module ParticipationsFull
           extend ActiveSupport::Concern
 
           included do
+            alias_method_chain :person_attributes, :pbs
             alias_method_chain :build_attribute_labels, :pbs
           end
 
+          def person_attributes_with_pbs
+            person_attributes_without_pbs + [:has_siblings_in_event]
+          end
+
           def build_attribute_labels_with_pbs
             build_attribute_labels_without_pbs.tap do |labels|
               labels[:bsv_days] = ::Event::Participation.human_attribute_name(:bsv_days)
+              labels[:has_siblings_in_event] = 
+                ::Event::Participation.human_attribute_name(:has_siblings_in_event)
             end
           end
         end
diff --git a/app/domain/pbs/export/tabular/people/people_full.rb b/app/domain/pbs/export/tabular/people/people_full.rb
index 068f2d954..e9b668d31 100644
--- a/app/domain/pbs/export/tabular/people/people_full.rb
+++ b/app/domain/pbs/export/tabular/people/people_full.rb
@@ -17,8 +17,24 @@ module PeopleFull
           end
 
           def person_attributes_with_pbs
-            person_attributes_without_pbs + [:id, :layer_group_id, :pbs_number]
+            attrs = person_attributes_without_pbs + [:id, :layer_group_id, :pbs_number]
+            attrs += [:has_siblings_in_layer] if @group.present?
+            attrs
           end
+
+          def initialize(list, group = nil)
+            super(list)
+            @group = group
+          end
+
+          private
+
+          def row_for(entry, format = nil)
+            return super unless row_class == ::Export::Tabular::People::PersonRow && 
+                                               @group.present?
+            row_class.new(entry, format, @group)
+          end
+
         end
       end
     end
diff --git a/app/domain/pbs/export/tabular/people/person_row.rb b/app/domain/pbs/export/tabular/people/person_row.rb
index 0c4e61d8c..0f0a05324 100644
--- a/app/domain/pbs/export/tabular/people/person_row.rb
+++ b/app/domain/pbs/export/tabular/people/person_row.rb
@@ -12,6 +12,11 @@ module People
         module PersonRow
           extend ActiveSupport::Concern
 
+          def initialize(entry, format = nil, group = nil)
+            super(entry, format)
+            @group = group 
+          end
+
           def salutation
             entry.salutation_value
           end
@@ -24,6 +29,10 @@ def layer_group_id
             entry.try(:primary_group).try(:layer_group).try(:id)
           end
 
+          def has_siblings_in_layer
+            ::Person::FamilyMemberFinder.new(entry)
+                                        .family_members_in_context(@group, kind: :sibling)&.any?
+          end
         end
       end
     end
diff --git a/app/domain/person/family_member_finder.rb b/app/domain/person/family_member_finder.rb
new file mode 100644
index 000000000..84776cbdc
--- /dev/null
+++ b/app/domain/person/family_member_finder.rb
@@ -0,0 +1,33 @@
+#  Copyright (c) 2023, Pfadibewegung Schweiz. This file is part of
+#  hitobito_pbs and licensed under the Affero General Public License version 3
+#  or later. See the COPYING file at the top-level directory or at
+#  https://github.com/hitobito/hitobito_pbs.
+
+class Person::FamilyMemberFinder
+  attr_reader :person
+
+  def initialize(person)
+    @person = person
+  end
+
+  def family_members_in_layer(group, kind: :sibling)
+    Role.joins(person: :family_members)
+      .where(group: group.groups_in_same_layer,
+             person: { family_members: { kind: kind, other: person } })
+  end
+
+  def family_members_in_event(event, kind: :sibling)
+    Event::Participation.joins(person: :family_members)
+      .where(person: { family_members: { kind: kind, other: person } },
+             event: event)
+  end
+
+  def family_members_in_context(context, kind: :sibling)
+    case context
+    when Event
+      family_members_in_event(context, kind: kind)
+    when Group
+      family_members_in_layer(context, kind: kind)
+    end
+  end
+end
diff --git a/app/jobs/pbs/export/event_participations_export_job.rb b/app/jobs/pbs/export/event_participations_export_job.rb
index 3ff4f3a28..b899b17f3 100644
--- a/app/jobs/pbs/export/event_participations_export_job.rb
+++ b/app/jobs/pbs/export/event_participations_export_job.rb
@@ -33,5 +33,10 @@ def unfiltered_participants
       references(:people).
       distinct
   end
+  
+  def data
+    return super unless exporter == ::Export::Tabular::People::ParticipationsFull
+    ::Export::Tabular::People::ParticipationsFull.export(@format, entries, @filter.event)
+  end
 
 end
diff --git a/app/jobs/pbs/export/people_export_job.rb b/app/jobs/pbs/export/people_export_job.rb
index be7926ac7..162d1d2aa 100644
--- a/app/jobs/pbs/export/people_export_job.rb
+++ b/app/jobs/pbs/export/people_export_job.rb
@@ -13,8 +13,12 @@ module Pbs::Export::PeopleExportJob
   end
 
   def exporter_with_detail
-    return Pbs::Export::Tabular::People::HouseholdsFull if  @options[:household_details]
+    return Pbs::Export::Tabular::People::HouseholdsFull if @options[:household_details]
     exporter_without_detail
   end
 
+  def data
+    return super unless exporter == ::Export::Tabular::People::PeopleFull
+    ::Export::Tabular::People::PeopleFull.export(@format, entries, group)
+  end
 end
diff --git a/app/models/pbs/person.rb b/app/models/pbs/person.rb
index c3c6f71ca..b2f87d6a0 100644
--- a/app/models/pbs/person.rb
+++ b/app/models/pbs/person.rb
@@ -62,8 +62,7 @@ module Pbs::Person
 
     alias_method_chain :full_name, :title
 
-    i18n_boolean_setter :brother_and_sisters, :prefers_digital_correspondence
-
+    i18n_boolean_setter :prefers_digital_correspondence
 
     belongs_to :kantonalverband, class_name: 'Group' # might also be Group::Bund
     has_many :crises, foreign_key: :creator_id
diff --git a/app/serializers/pbs/event_participation_serializer.rb b/app/serializers/pbs/event_participation_serializer.rb
index 1954b1f88..03ca236c8 100644
--- a/app/serializers/pbs/event_participation_serializer.rb
+++ b/app/serializers/pbs/event_participation_serializer.rb
@@ -16,6 +16,10 @@ module Pbs::EventParticipationSerializer
           translated_label: number.translated_label
         }
       end)
+
+      property(:has_siblings_in_event, 
+               ::Person::FamilyMemberFinder.new(item.person)
+                 .family_members_in_context(item.event, kind: :sibling).any?)
     end
   end
 end
diff --git a/app/serializers/pbs/person_serializer.rb b/app/serializers/pbs/person_serializer.rb
index 693df326a..c5f043492 100644
--- a/app/serializers/pbs/person_serializer.rb
+++ b/app/serializers/pbs/person_serializer.rb
@@ -11,9 +11,13 @@ module Pbs::PersonSerializer
   included do
     extension(:details) do |_|
       map_properties :pbs_number, :salutation_value, :correspondence_language,
-                     :prefers_digital_correspondence, :grade_of_school, :brother_and_sisters,
-                     :entry_date, :leaving_date
+                     :prefers_digital_correspondence, :grade_of_school, :entry_date, :leaving_date
+
+      if context[:group].present?
+        property :has_siblings_in_layer, item.siblings_in_context(context[:group]).any?
+      end
     end
+
   end
 
 end
diff --git a/app/views/people/_details_pbs.html.haml b/app/views/people/_details_pbs.html.haml
index 669040b9a..406750dfd 100644
--- a/app/views/people/_details_pbs.html.haml
+++ b/app/views/people/_details_pbs.html.haml
@@ -4,6 +4,17 @@
 -#  https://github.com/hitobito/hitobito_pbs.
 
 = render_attrs(entry, :pbs_number, :salutation, :correspondence_language,
-                      :grade_of_school, :brother_and_sisters)
+                      :grade_of_school)
+
+%dl.dl-horizontal
+  - sibling_context = parent.try(:layer_group) || parent
+  - siblings_in_context = entry.siblings_in_context(sibling_context)
+  = labeled(t('people.fields_pbs.siblings_in_context', context: sibling_context)) do
+    - if siblings_in_context.any?
+      = t('global.yes')
+      = simple_list(siblings_in_context, class: 'unstyled mb-0') do |sibling_role|
+        -  assoc_link(sibling_role.person)
+    - else
+      = t('global.no')
 
 = render_attrs(entry, :entry_date, :leaving_date)
diff --git a/app/views/people/_fields_pbs.html.haml b/app/views/people/_fields_pbs.html.haml
index 9db0179f0..37e5ece52 100644
--- a/app/views/people/_fields_pbs.html.haml
+++ b/app/views/people/_fields_pbs.html.haml
@@ -17,6 +17,3 @@
 
 = field_set_tag do
   = f.labeled_input_fields(:entry_date, :leaving_date)
-
-= field_set_tag do
-  = f.labeled_boolean_field(:brother_and_sisters, caption: t('.in_abteilung'))
diff --git a/config/locales/models.pbs.de.yml b/config/locales/models.pbs.de.yml
index c6fe931cb..cb1ca0a2e 100644
--- a/config/locales/models.pbs.de.yml
+++ b/config/locales/models.pbs.de.yml
@@ -1243,6 +1243,7 @@ de:
         additional_information: Wie möchtest du dich im Anlass ernähren? Was sind deine Essgewohnheiten?
         bsv_days: BSV-Tage
         j_s_data_sharing_accepted: J+S Datenweitergabe
+        has_siblings_in_event: Geschwister im Anlass
 
       event/question:
         pass_on_to_supercamp: An übergeordnetes Lager weitergeben
@@ -1259,8 +1260,7 @@ de:
         leaving_date: Austrittsdatum
         j_s_number: J+S Personennummer
         correspondence_language: Korrespondenzsprache
-        brother_and_sisters: Geschwister
-        relations_to_tails: Geschwister
+        has_siblings_in_layer: Geschwister in der Ebene
         kv: Kantonalverband
         prefers_digital_correspondence: Digitale Korrespondenz bevorzugt
 
diff --git a/config/locales/views.pbs.de.yml b/config/locales/views.pbs.de.yml
index 5c344f9b3..15d7cfaa7 100644
--- a/config/locales/views.pbs.de.yml
+++ b/config/locales/views.pbs.de.yml
@@ -348,7 +348,7 @@ de:
       no_sensitive_information: In diesem Feld keine besonders schützenswerte Personendaten erfassen.
     fields_pbs:
       non_automatic_field: Dies ist kein automatisches Feld und muss manuell angepasst werden.
-      in_abteilung: (in der Abteilung)
+      siblings_in_context: Geschwister in %{context}
     qualification_buttons_pbs:
       print_course_confirmation: Kursbestätigung drucken
     household_attrs_pbs:
diff --git a/db/migrate/20230912120642_remove_brother_and_sister_from_persons.rb b/db/migrate/20230912120642_remove_brother_and_sister_from_persons.rb
new file mode 100644
index 000000000..c12f0cabd
--- /dev/null
+++ b/db/migrate/20230912120642_remove_brother_and_sister_from_persons.rb
@@ -0,0 +1,5 @@
+class RemoveBrotherAndSisterFromPersons < ActiveRecord::Migration[6.1]
+  def change
+    remove_column :people, :brother_and_sisters, :boolean, default: false, null: false
+  end
+end
diff --git a/lib/hitobito_pbs/wagon.rb b/lib/hitobito_pbs/wagon.rb
index b2852414c..63f66d52c 100644
--- a/lib/hitobito_pbs/wagon.rb
+++ b/lib/hitobito_pbs/wagon.rb
@@ -118,7 +118,7 @@ class Wagon < Rails::Engine
       ### controllers
       PeopleController.permitted_attrs += [:salutation, :title, :grade_of_school, :entry_date,
                                            :leaving_date, :j_s_number, :correspondence_language,
-                                           :prefers_digital_correspondence, :brother_and_sisters]
+                                           :prefers_digital_correspondence]
       GroupsController.permitted_attrs += [:hostname]
       Event::KindsController.permitted_attrs += [:documents_text, :campy, :can_have_confirmations,
                                                  :confirmation_name]
diff --git a/spec/domain/person/family_member_finder_spec.rb b/spec/domain/person/family_member_finder_spec.rb
new file mode 100644
index 000000000..96b7236ca
--- /dev/null
+++ b/spec/domain/person/family_member_finder_spec.rb
@@ -0,0 +1,93 @@
+# encoding: utf-8
+
+#  Copyright (c) 2017, Pfadibewegung Schweiz. This file is part of
+#  hitobito_pbs and licensed under the Affero General Public License version 3
+#  or later. See the COPYING file at the top-level directory or at
+#  https://github.com/hitobito/hitobito_pbs.
+
+require 'spec_helper'
+
+describe Person::FamilyMemberFinder do
+
+  let(:service) { described_class.new(person) }
+  let(:person) { Fabricate(:person) }
+  let(:sibling) { Fabricate(:person) }
+
+  let!(:sibling_relation) { Fabricate(:family_member, person: person, other: sibling, kind: :sibling) }
+
+  describe '#family_members_in_event' do
+
+    let(:person_event) { Fabricate(:event) }
+    let!(:person_participation) { Fabricate(:event_participation, person: person, event: person_event) }
+    let(:sibling_event) { Fabricate(:event) }
+    let!(:sibling_participation) { Fabricate(:event_participation, person: sibling, event: sibling_event) }
+
+    subject do
+      service.family_members_in_event(person_event, kind: :sibling)
+    end
+
+    context 'without siblings' do
+      let!(:sibling_relation) { nil }
+      it { is_expected.to be_empty }
+    end
+
+    context 'with siblings in different events' do
+      it { is_expected.to be_empty }
+    end
+
+    context 'with siblings in same event' do
+      let(:sibling_event) { person_event }
+      it { is_expected.to contain_exactly(sibling_participation) }
+    end
+
+    context 'with siblings with deleted role in same group' do
+      let!(:sibling_participation) { Fabricate(:event_participation, person: sibling, event: sibling_event, active: false) }
+      it { is_expected.to be_empty }
+    end
+
+  end
+
+  describe '#family_members_in_layer' do
+
+    let(:layer) { Fabricate(Group::Abteilung.name) }
+
+    let(:person_group) { Fabricate(Group::Pfadi.name, parent: layer)}
+    let!(:person_role) { Fabricate(person_group.default_role.name, person: person, group: person_group) }
+
+    let(:sibling_group) { Fabricate(Group::Woelfe.name, parent: layer)}
+    let!(:sibling_role) { Fabricate(sibling_group.default_role.name, person: sibling, group: sibling_group) }
+
+    subject do
+      service.family_members_in_layer(person_group, kind: :sibling)
+    end
+
+    context 'without siblings' do
+      let!(:sibling_relation) { nil }
+      it { is_expected.to be_empty }
+    end
+
+    context 'with siblings in different groups' do
+      let(:sibling_group) { Fabricate(Group::Woelfe.name, parent: Fabricate(Group::Abteilung.name))}
+      it { is_expected.to be_empty }
+    end
+
+    context 'with siblings in same group' do
+      let(:sibling_group) { person_group }
+      it { is_expected.to contain_exactly(sibling_role) }
+    end
+
+    context 'with siblings in same layer' do
+      it { is_expected.to contain_exactly(sibling_role) }
+    end
+
+    context 'with siblings with deleted role in same group' do
+      let!(:sibling_role) do  
+        Fabricate(sibling_group.default_role.name, person: sibling, group: sibling_group, 
+                                                   created_at: 2.months.ago, deleted_at: 1.month.ago)
+      end
+      it { is_expected.to be_empty }
+    end
+
+  end
+
+end