public function getGroupsPairs()
    {
        // Check or init cache
        if (!self::$cached_group_pairs) {
            $user_collection = new AdminUserGroupRepository;
            $user_collection->addOrderByField('title');
            $pairs = $user_collection->getPairs('title');

            self::$cached_group_pairs = $pairs;
        }

        return self::$cached_group_pairs;
    }