I'm in the same position as you.
Let me guess you actually hate this person but you won't admit it because if you ever said anything to anyone they would all get mad at you
and then you would sound like a witch even though that other girl just needs a reality check.
I think you should just completely ignore her and wait until she or another close friend who hangs out with her asks why and than tell them off and If they don't understand than I guess none of you guys were actually good friends to begin with
hope this helped :)
I know the heartfelt pain you must be in.