diff --git a/Parser/Type.php b/Parser/Type.php
index 2e334e8..5b4145f 100644
--- a/Parser/Type.php
+++ b/Parser/Type.php
@@ -49,6 +49,11 @@ abstract class XML_Feed_Parser_Type
      */
     public $entries = array();
 
+    /**
+     * Store mappings between entry IDs and their position in the feed
+     */
+    public $idMappings = array();
+
     /**
      * Proxy to allow use of element names as method names
      *