I want to be able to port forward but only to specific ip addresses

I would like to port forward to allow my friends to play games that I host from my network. However: I do not want to be opening my port to the entire internet. I would like to have a setting such that my router can automatically block ip addresses that don't fall between certain ranges that I set up.

It's not a perfect solution, but as far as I can tell you're not able to designate this anywhere in the xfi router, so it's better than what we have right now.