public function is_available()
{
// Leader of any groups?
$sql = 'SELECT group_id
FROM ' . USER_GROUP_TABLE . '
WHERE user_id = ' . (int) $this->user->data['user_id'] . '
AND group_leader = 1';
$result = $this->db->sql_query_limit($sql, 1);
$row = $this->db->sql_fetchrow($result);
$this->db->sql_freeresult($result);
return !empty($row) ? true : false;
}