Get signed in users groups from external script

[blackvoid]

Hi
I would like to get which groups a signed in user is from a external script.
In phpBB you would do it like this to see if the user has admin permissions.

<?php
    define('IN_PHPBB', true);
    $phpbb_root_path = (defined('PHPBB_ROOT_PATH')) ? PHPBB_ROOT_PATH : '../forum';
    $phpEx = substr(strrchr(__FILE__, '.'), 1);
    include($phpbb_root_path . 'common.' . $phpEx);
    $user->session_begin();
    $auth->acl($user->data);
    if($auth->acl_get('a_'))
    {
        $isAuth = true;
    }
    else
    {
        $isAuth = false;
    }
?>

I need to do this, but with XenForo. Does anyone know how to do this?