How not to parse url from guests?

[Hondo]

Hi,
Subs.php about line 1700 (1.1 Rc1):

$data = preg_replace(array('~(?<=[\s>\.(;\'"]|^)((?:http|https|ftp|ftps)://[\w\-_%@:|]+(?:\.[\w\-_%]+)*(?::\d+)?(?:/[\w\-_\~%\.@,\?&;=#+:\'\\\\]*|[\(\{][\w\-_\~%\.@,\?&;=#(){}+:\'\\\\]*)*[/\w\-_\~%@\?;=#}\\\\])~i', '~(?<=[\s>(\'<]|^)(www(?:\.[\w\-_]+)+(?::\d+)?(?:/[\w\-_\~%\.@,\?&;=#+:\'\\\\]*|[\(\{][\w\-_\~%\.@,\?&;=#(){}+:\'\\\\]*)*[/\w\-_\~%@\?;=#}\\\\])~i'), array('$1', '$1'), $data);

I want to do this only at registered members. The method seams clear: Changing array('$1', '$1') to array('', ''),  but how to know if the poster is a guest or not?

Andreas