public function add($item, $extraFields = null)
 {
     // Get Group.ID
     $itemID = null;
     if (is_numeric($item)) {
         $itemID = $item;
     } else {
         if ($item instanceof Group) {
             $itemID = $item->ID;
         }
     }
     // Check if this group is allowed to be added
     if ($this->canAddGroups(array($itemID))) {
         parent::add($item, $extraFields);
     }
 }