public function addTermsFactory( $factory_name, $taxonomy ) {
		// do nothing if factory name is already taken
		if ( ! empty( $this->_factories[ $factory_name ] ) ) {
			return false;
		}

		// do nothing if a taxonomy doesn't exist
		if ( ! taxonomy_exists( $taxonomy ) ) {
			return false;
		}

		$this->_factories[ $factory_name ] = new TermsFactory( $taxonomy );
		
		return true;
	}