diff --git a/libs/libarchopenfpga/src/read_xml_tile_annotation.cpp b/libs/libarchopenfpga/src/read_xml_tile_annotation.cpp
index 6b27d0017d..d01b81b64f 100644
--- a/libs/libarchopenfpga/src/read_xml_tile_annotation.cpp
+++ b/libs/libarchopenfpga/src/read_xml_tile_annotation.cpp
@@ -125,6 +125,22 @@ static void read_xml_tile_global_port_annotation(
   }
 }
 
+/********************************************************************
+ * Parse XML description for an interconnection annotation
+ * under a <global_port> XML node
+ *******************************************************************/
+static void read_xml_tile_merge_port_annotation(
+  pugi::xml_node& xml_tile, const pugiutil::loc_data& loc_data,
+  openfpga::TileAnnotation& tile_annotation) {
+  const std::string& tile_attr =
+    get_attribute(xml_tile, "tile", loc_data).as_string();
+
+  const std::string& port_attr =
+    get_attribute(xml_tile, "port", loc_data).as_string();
+  
+  tile_annotation.add_merge_subtile_ports(tile_attr, port_attr);
+}
+
 /********************************************************************
  * Top function to parse XML description about tile annotation
  *******************************************************************/
@@ -146,11 +162,15 @@ openfpga::TileAnnotation read_xml_tile_annotations(
    */
   for (pugi::xml_node xml_tile_global_port : xml_annotations.children()) {
     /* Error out if the XML child has an invalid name! */
-    if (xml_tile_global_port.name() != std::string("global_port")) {
-      bad_tag(xml_tile_global_port, loc_data, xml_annotations, {"global_port"});
+    if (xml_tile_global_port.name() == std::string("global_port")) {
+      read_xml_tile_global_port_annotation(xml_tile_global_port, loc_data,
+                                           tile_annotations);
+    } else if (xml_tile_global_port.name() == std::string("merge_subtile_ports")) {
+      read_xml_tile_merge_port_annotation(xml_tile_global_port, loc_data,
+                                          tile_annotations);
+    } else {
+      bad_tag(xml_tile_global_port, loc_data, xml_annotations, {"global_port or merge_subtile_ports"});
     }
-    read_xml_tile_global_port_annotation(xml_tile_global_port, loc_data,
-                                         tile_annotations);
   }
 
   return tile_annotations;
diff --git a/libs/libarchopenfpga/src/tile_annotation.cpp b/libs/libarchopenfpga/src/tile_annotation.cpp
index 7cf41f02e1..d9ac5c0f56 100644
--- a/libs/libarchopenfpga/src/tile_annotation.cpp
+++ b/libs/libarchopenfpga/src/tile_annotation.cpp
@@ -2,8 +2,11 @@
  * Member functions for class TileAnnotation
  ***********************************************************************/
 #include "tile_annotation.h"
+#include "command_exit_codes.h"
+#include <algorithm>
 
 #include "vtr_assert.h"
+#include "vtr_log.h"
 
 /* namespace openfpga begins */
 namespace openfpga {
@@ -20,6 +23,24 @@ TileAnnotation::global_port_range TileAnnotation::global_ports() const {
   return vtr::make_range(global_port_ids_.begin(), global_port_ids_.end());
 }
 
+std::vector<std::string> tiles_to_merge_ports() const {
+  std::vector<std::string> tile_names;
+  for (auto it = tile_ports_to_merge_.begin(); it != tile_ports_to_merge_.end(); it++) {
+    tile_names.push_back(it->first);
+  }
+  return tile_names;
+}
+
+std::vector<std::string> tile_ports_to_merge(const std::string& tile_name) const {
+  std::vector<std::string> port_names;
+  const auto& result = tile_ports_to_merge_.find(tile_name);
+  if (result == tile_ports_to_merge.end()) {
+    VTR_LOG_WARN("Tile '%s' does not contain any ports to merge!\n", tile_name.c_str());
+    return port_names;
+  }
+  return result.second;
+}
+
 /************************************************************************
  * Public Accessors
  ***********************************************************************/
@@ -178,4 +199,21 @@ bool TileAnnotation::valid_global_port_attributes(
   return ((0 == attribute_counter) || (1 == attribute_counter));
 }
 
+int TileAnnotation::add_merge_subtile_ports(const std::string& tile_name, const std::string& port_name) {
+  auto result = tile_ports_to_merge_.find(tile_name);
+  if (result == tile_ports_to_merge_.end()) {
+    /* Empty list: add a new element */
+    tile_ports_to_merge_[tile_name].push_back(port_name);
+  } else {
+    /* Check if the port name is already in the list, if yes, error out */
+    if (result->second.end() == std::find(result->secnd.begin(), result->second.end(), port_name)) {
+      tile_ports_to_merge_[tile_name].push_back(port_name);
+    } else {
+      VTR_LOG_ERROR("Port '%s' has already been defined twice for tile '%s' to be merged!", port_name.c_str(), tile_name.c_str());
+      return CMD_EXEC_FATAL_ERROR;
+    }
+  }
+  return CMD_EXEC_SUCCESS;
+}
+
 }  // namespace openfpga
diff --git a/libs/libarchopenfpga/src/tile_annotation.h b/libs/libarchopenfpga/src/tile_annotation.h
index ddf9511090..de5a40a082 100644
--- a/libs/libarchopenfpga/src/tile_annotation.h
+++ b/libs/libarchopenfpga/src/tile_annotation.h
@@ -39,6 +39,8 @@ class TileAnnotation {
 
  public: /* Public accessors: aggregators */
   global_port_range global_ports() const;
+  std::vector<std::string> tiles_to_merge_ports() const;
+  std::vector<std::string> tile_ports_to_merge(const std::string& tile_name) const;
 
  public: /* Public accessors */
   std::string global_port_name(const TileGlobalPortId& global_port_id) const;
@@ -77,6 +79,8 @@ class TileAnnotation {
   void set_global_port_default_value(const TileGlobalPortId& global_port_id,
                                      const size_t& default_value);
 
+  int add_merge_subtile_ports(const std::string& tile_name, const std::string& port_name);
+
  public: /* Public validator */
   bool valid_global_port_id(const TileGlobalPortId& global_port_id) const;
   /* Validate attributes of a given global port
@@ -102,6 +106,9 @@ class TileAnnotation {
 
   /* A fast lookup for port names */
   std::map<std::string, TileGlobalPortId> global_port_name2ids_;
+
+  /* Merge port information for tiles */
+  std::map<std::string, std::vector<std::string>> tile_ports_to_merge_; // tile_name -> port_name
 };
 
 }  // namespace openfpga
diff --git a/libs/libarchopenfpga/src/write_xml_tile_annotation.cpp b/libs/libarchopenfpga/src/write_xml_tile_annotation.cpp
index af6bab25a5..5bccbc2c69 100644
--- a/libs/libarchopenfpga/src/write_xml_tile_annotation.cpp
+++ b/libs/libarchopenfpga/src/write_xml_tile_annotation.cpp
@@ -87,6 +87,25 @@ static void write_xml_tile_annotation_global_port(
      << "</global_port>";
 }
 
+/********************************************************************
+ * A writer to output a device variation in a technology library to XML format
+ *******************************************************************/
+static void write_xml_tile_annotation_subtile_port_to_merge(
+  std::fstream& fp, const char* fname,
+  const std::string& tile_name,
+  const std::string& port_name) {
+  /* Validate the file stream */
+  openfpga::check_file_stream(fname, fp);
+
+  fp << "\t\t"
+     << "<merge_subtile_ports ";
+
+  write_xml_attribute(fp, "tile", tile_name.c_str());
+  write_xml_attribute(fp, "port", port_name.c_str());
+
+  fp << "/>";
+}
+
 /********************************************************************
  * A writer to output tile annotations to XML format
  *******************************************************************/
@@ -109,6 +128,11 @@ void write_xml_tile_annotations(std::fstream& fp, const char* fname,
     write_xml_tile_annotation_global_port(fp, fname, tile_annotation,
                                           global_port_id);
   }
+  for (std::string tile_name : tile_annotation.tiles_to_merge_ports()) {
+    for (std::string port_name : tile_annotation.tile_ports_to_merge(tile_name)) {
+      write_xml_tile_annotation_subtile_port_to_merge(fp, fname, tile_name, port_name);
+    }
+  }
 
   /* Write the root node for pb_type annotations */
   fp << "\t"