one forum under two categories?

[MensLounge]

Hey im running a small forum at the moment and the idea is that there will be a singles category and a relationship one... they will both have forums specific to the title.

But what i want to do is include the in between forums that apply to both categories and have them both show up in the two different categories.

Im aware that i could link them to the forum and make the forum not active in vbulletin, but id prefer a way so that all the posts show up in each section rather than a dodgy link.

any possible way?