Stacking group selection?

I'm dealing with a pretty big array of lights. I'm learning a lot more about using this console as a result. Is there a way to stack group selection? Erm... let's say I have a group that's all the onstage fixtures for the whole rig, and then I have a group for each pod. Is there a way to somehow "stack" these two groups so it will only select the onstage fixtures of the selected pod? Or, thinking about it the other way, knocking out all the other fixtures that aren't part of both groups?

I'm trying to streamline programming and avoiding creating a billion groups