Create individual custom islands and select them as adverts between post 1 & 2 in forum settings.
Basically you can create any you want on that principle.
I have +40 individual custom islands for each forum between post 1 and 2.
the advantage is after the long slog of creating them is you can still have google and your paid advertiser, or no google, just depends what your charging for a selection.
Sorry not got the time to hunt out the correct places in the forum settings.
hope that helps.
