protected function get_group_member_ids() {
		global $wpdb;

		if ( is_array( $this->group_member_ids ) ) {
			return $this->group_member_ids;
		}

		// Fetch **all** invited users.
		$pending_invites = groups_get_invites( array(
			'item_id'     => $this->query_vars['group_id'],
			'invite_sent' => 'sent',
			'fields'      => 'user_ids'
		) );

		// This is a clue that we only want the invitations.
		if ( false === $this->query_vars['is_confirmed'] ) {
			return $pending_invites;
		}

		/**
		 * Otherwise, we want group members _and_ users with outstanding invitations,
		 * because we're doing an "exclude" query.
		 */
		$bp  = buddypress();
		$sql = array(
			'select'  => "SELECT user_id FROM {$bp->groups->table_name_members}",
			'where'   => array(),
			'orderby' => '',
			'order'   => '',
			'limit'   => '',
		);

		/** WHERE clauses *****************************************************/

		// Group id
		$sql['where'][] = $wpdb->prepare( 'group_id = %d', $this->query_vars['group_id'] );

		// Join the query part
		$sql['where'] = ! empty( $sql['where'] ) ? 'WHERE ' . implode( ' AND ', $sql['where'] ) : '';

		/** ORDER BY clause ***************************************************/
		$sql['orderby'] = 'ORDER BY date_modified';
		$sql['order']   = 'DESC';

		/** LIMIT clause ******************************************************/
		$this->group_member_ids = $wpdb->get_col( "{$sql['select']} {$sql['where']} {$sql['orderby']} {$sql['order']} {$sql['limit']}" );

		return array_merge( $this->group_member_ids, $pending_invites );
	}