The next time I hear a chair say "does anyone have a topic?" and I feel bothered ~ I think I will raise my hand and say "Where do resentments come from?"
I have always associated "cross talk" with people speaking out of turn (interrupting someone else), or folks enjoying a small side conversation which should be taken outside. I mainly heard the "no crosstalk" at the various rehabs I have been a resident of...but that was always specific to people holding side conversations.