I think that when you are a professional, it's difficult to keep your feelings about what other professionals do to yourself. Your T's should not be making snarky comments to you, though. It is an example of triangulation, having a third person sort of in the room, and they are bring the other one in (not you), and it puts something into your therapy that shouldn't be there.

I like Bill's suggestion about raising it the next time someone says the snarky thing. Personally, if it were me and it were bugging me right now, I would say, "I feel, T, that you have made the occasional side comment about other T, something negative about her, and it has bothered me when this happens. I haven't been able to speak up about it until now, but I want to raise this with you."