Index: groups_event_handler.php
===================================================================
--- groups_event_handler.php	(revision 13557)
+++ groups_event_handler.php	(working copy)
@@ -38,8 +38,11 @@
 								FROM ' . $table_name . '
 								WHERE PortalUserId = ' . (int)$user_id;
 						$group_ids = $this->Conn->GetCol($sql);
-						array_push($group_ids, 14, 15); // Guest & Everyone groups are set dynamically
 
+						// add system groups
+						array_push($group_ids, $this->Application->ConfigValue('User_GuestGroup')); // Guest
+						array_push($group_ids, $this->Application->ConfigValue('User_LoggedInGroup')); // Everyone
+
 						$object->addFilter('already_member_filter', '%1$s.GroupId NOT IN ('.implode(',', $group_ids).')');
 					}
 					break;