Separate Categories - Gotta Be a Better Way
 

I've looked over a lot of styles and a lot of separate category tutorials. Everyone does it different, but not all of them have valid HTML. So far the only one that I can make work is the one from vBulletin.com where they have you add the if conditional around the starting code:

But to make your whole forum valid, you have to make this as an array, where you add all the uppermost forum IDs to the conditional. My questions is, has anyone come up with a better way? I'd like to be able to offer my customers valid HTML without the special instructions of adding the ID numbers.

NOTE: Even some very popular premium styles do this differently, without the if conditions as part of the templates. But where they fall short is when your forum configurations begin to get more complex on forumdisplay.php. That's why the one above is the only one working for me so far.