[nighthalk]

I would think you could just write a mod with if statements that will only show what forum id you want to show.
Something like this below.

if ( $_SERVER['HTTP_HOST'] == "domain.com" ) {
code to show specific forums.
}
else if ( $_SERVER['HTTP_HOST'] == "domain2.com" ) {
code to show specific forums for this domain
}
else {
code to show default forum.
}

Would take a bit of playing with but I sure it could be done.

I do believe it would only need one licence this way. Don't quote me on the licence part