public function groupWhere($callback)
    {
        $origQuery = $this->query; //get original raw of query
        $this->query = ''; //clear orig part in order to get only group part
        $qb = $callback($this); //get queryBuilder from call back
        $query = $qb->query.')'; //get group part of query from queryBuilder with )
        $query = preg_replace('/AND /', 'AND (', $query, 1); //add (
        $this->query = $origQuery.$query; //make full query
    }