Rant: Our club nearly tore itself apart over a 40 minute meeting

Last Thursday at the Panera on Maple Ave we had 11 people show up to talk about The Overstory and the talk turned into a fight about next month's pick. Two people got loud, one walked out, and I was sitting there with my cold soup trying to figure out how to fix it. I pulled up the library's event page on my phone and set a hard 40 minute cap for the book talk with 10 minutes for picking the next read at the end. It worked so well that we actually finished the discussion and picked a book with barely any arguing, the whole thing took 52 minutes. If your club has a member who turns every pick into a battle, what do you do, rules or just talk to them one on one?