Targeting ads to/excluding ads from specific forums

[waccoe.com]

Hi there - we are looking to try to manage advertising content by forum. Is this possible with either the standard Ad Manager or Commerce? 

 

As a sports based site, we have some gambling relevant content.  Ideally we'd like to put all gambling content in a specific forum and target gambling related ads directly at that forum (taking advantage of more generous ad terms).  But it is hard to see from relevant ad manager and commerce documentation that this sort of obvious thing to do is possible.  Or are we just being dumb?