I agree with the adding exercise, especially a long walk or a run before company arrives (if you know they are coming).

Also, along with the treats, add a water squirt bottle to your armory. When she is jumping up, squirt her in the face. It sure does get their attention! From there, give a command and the moment she responds, treat.

I've never had luck putting them in a back room either. They are social creatures and want to be with everyone. Just need some manners, lol.

Good luck!