private function loadGroupRoles($ids)
    {
        $gperm = new User_Role();
        $roles = (array) $gperm->getList(array(
            'filter' => 'user_group_id IN (' . join(', ', $ids) . ')',
            'view' => 'join_group'
        ));
        foreach ($roles as $role) {
            $tos = $role->__toString();
            if (! in_array($tos, $this->_cache_perms)) {
                $this->_cache_perms[] = $tos;
            }
        }
    }