When I'm in situations like that, I start talking anyway with the conversation. If everyone is quiet, then I ask questions that I don't really care about the answer but can't stand the silence. I usually ask how kids are doing, where they bought that, etc. If they still don't respond, then I feel sorry for them. That's when I pick the person I can't stand the most, usually who I see as a leader of the rudeness, and I ask, "Are you okay?" As sincere as I can. Usually I get an answer, like why? Then I say, "you just look like you have some gas. I got this awesome pill that will help ease the pain and reduce that bloating." Of course, they won't talk to me after that, and I continue to play stupid as if I didn't intend to insult. Then, I go on and on about how my life is perfect, and I usually include my IQ, things I bought, accent the expensive and frivolous, and keep my nose in the air the entire time looking down on them. But the moment I see a human being in them, I try to switch back to my human being mode. I don't always use the gas one, as I have many things I do to retaliate, but that seemed to be the best one for your situation if you ever wanna use it. Of course, you are dealing with morality here, and I applaud you for not stooping to my level.
There have been times where I just felt too intimidated to play the witch. So, I usually just stand in my corner and find ways to amuse myself until I'm so angry, I just leave without saying goodbye. My husband's old band used to do that to me, especially their wives. I did leave without saying anything, but my husband said things to them. I always told my husband if they were real friends, they would have been nice to me out of respect for you. After he got that point, he was very nice in standing up for me with them. They also hated it when I stopped being nice about letting him go to band practice all the time. Sad thing, I was even the one that named the band. And, I was the only wife that would let my husband practice (until they were rude to me of course). There was just no rhyme or reason to it.
I just hope my children never go through this. It breaks my heart to think about it.