Without seeing the true dynamic of the group and the positioning you could do a couple things.
If you NEG make sure it is a neg and not a insult. There is a fine line and in this situation you could get blown out quick.
Does she always interrupt people's conversations?(When you say this make sure you BL, and tone are good. You can get away with a ton of shit if you have the correct tone)(It needs to be in a way that you are almost not even asking the question. It is more of a statement although it will surely be answered) Implied to the two girls you were talking to. They will probably think it is funny and say Yes, laughing. Then it is important to engage the girl and bring her in. If you don't you will probably be doomed. She can ruin the set with EASE. You could then play nice with her and tell her to come in closer and you will catch her up.
Don't catch her up as the other two will lose interest. Continue where you left off, start a new thread, or repose the question without all the glitz. We were talking about who lied more guys or girls(Or the true statement I would say at this point is (We were talking about how girls lied WAY more than guys). That way it gets all the girls riled up. You can also point out that your target thinks girls are the biggest liars blah blah. You will get an immediate IOI or IOD from your target. This will immediately engage the set breaker in the topic and save you from being blown out.
There is some video on maybe youtube with Mystery talking about sets like these. Some of his information on the topic was pretty freaking solid if you ask me. I have no idea how to find it for you though but I am pretty certain I watched it a couple years ago or so.
His advice was a hundred times better than mine.
There are some witty fuckers on this board who could probably yield some better quips. Hopefully they will chime in.
