<?php
$options = array(
    'joins' => array(
        "JOIN (
            SELECT container_guid, MAX(time_updated) AS mtime
            FROM entities
            WHERE owner_guid = $user_guid
            GROUP BY container_guid
        ) AS q1 ON (e.guid = q1.container_guid AND e.type = 'group')"
    ),
    'order_by' => 'q1.mtime DESC',
    'limit' => 10,
);