Customizing Forumhome or Forumdisplay

[BigSoccer Tech.]

Is there a way to pass several forum (or category) ids to either index.php or forumdisplay.php to generate a custom listing of forums that isn't the whole listing or just one category listing?

For instance, I know I can pass a variable like this to index.php and have it only show one category:

  if ($_SERVER['PHP_SELF'] == '/forum/index.php')
  {
       $foruminfo['forumid'] = 79;
       $forumid=79;

But I've had no luck passing it 2 forum(category) IDs.

Thanks.