public function filter($key, $filter=null, $option=null) {
		if (is_int(strpos($key,'.'))) {
			list($key,$fkey) = explode('.',$key,2);
			if (!isset($this->relFilter[$key.'.']))
				$this->relFilter[$key.'.'] = array();
			$this->relFilter[$key.'.'][$fkey] = array($filter,$option);
		} else
			$this->relFilter[$key] = array($filter,$option);
		return $this;
	}