Gossip is Gossip. Having had a relationship go very far south with my mother and sister due to evil gossip, I would recommend that you do not get involved. I am sure they already know what your are going to say. Inevitably, it will come back to you that you were "eavesdropping" or what ever other evil speak someone says about you. I can't fix someone elses behaviour as much as you would like to try.
God bless and don't let the "mean and thoughtless" people get you down.
jmd