You can add a PHP script to be parsed server-side upon opening the patcher. That option is from the Tools/config.ini file, for noticeboxes. Your PHP script could load a webpage for that purpose.
There's no other way I know than this one, but maybe you can place a small noticebox that gets the info and another noticebox for the regular announcements you want to put there.
I'll move this topic to client-side support since it fits more there than on RO (ingame) scripts section.