diff --git a/plugins/module_utils/interface_group.py b/plugins/module_utils/interface_group.py
index 2021488e..bffd4b07 100644
--- a/plugins/module_utils/interface_group.py
+++ b/plugins/module_utils/interface_group.py
@@ -77,31 +77,14 @@ def _validate_params(self):
             self.module.fail_json(msg='Group name cannot have more than 15 characters.')
         if re.match('[0-9]$', params['name']) is not None:
             self.module.fail_json(msg='Group name cannot end with a digit.')
+        # Make sure list of interfaces is a unique set
+        if len(params['members']) > len(set(params['members'])):
+            self.module.fail_json(msg='List of members is not unique.')
         # TODO - check that name isn't in use by any interfaces
 
     ##############################
     # XML processing
     #
-    def _copy_and_add_target(self):
-        """ create the XML target_elt """
-        self.pfsense.copy_dict_to_element(self.obj, self.target_elt)
-
-    def _copy_and_update_target(self):
-        """ update the XML target_elt """
-        before = self.pfsense.element_to_dict(self.target_elt)
-        changed = self.pfsense.copy_dict_to_element(self.obj, self.target_elt)
-        if self._remove_deleted_params():
-            changed = True
-
-        self.diff['before'] = before
-        if changed:
-            self.diff['after'] = self.pfsense.element_to_dict(self.target_elt)
-            self.result['changed'] = True
-        else:
-            self.diff['after'] = self.obj
-
-        return (before, changed)
-
     def _create_target(self):
         """ create the XML target_elt """
         self.diff['before'] = ''
@@ -110,8 +93,13 @@ def _create_target(self):
 
     def _find_target(self):
         """ find the XML target_elt """
-        target_elt = self.root_elt.findall("ifgroupentry[ifname='{0}']".format(self.obj['ifname']))[0]
-        return target_elt
+        result = self.root_elt.findall("ifgroupentry[ifname='{0}']".format(self.obj['ifname']))
+        if len(result) == 1:
+            return result[0]
+        elif len(result) > 1:
+            self.module.fail_json(msg='Found multiple interface groups for name {0}.'.format(self.obj['ifname']))
+        else:
+            return None
 
     def _pre_remove_target_elt(self):
         """ processing before removing elt """