It’s never worked well for me; usually when a friend from group A meets a friend from group B, they either hit it off and ignore me, or don’t get along at all. I guess a good idea would be to find something that all (or most) of your friends enjoy, and either bring it into conversation (maybe they all have pets, or love The Office, or enjoy HALO, etc.) or make it part of what you do as a group (Can’t Stop the Serenity showing, for instance, brings many people together but it’s the wrong time of year for that.) If you really want it to work between your friends, you are going to have do some work and act as a “bridge” or “translator” of sorts.