Consiglio: Request: When someone is being patronizing, how can you call them out on it without literally calling them out on it in a group situation?

I have an ex boss who always has to patronize me in a group settings ever since I got a promotion to be on his level professionally. If we are in a group, how do I make everyone see that he’s being an asshole? I don’t want to say “stop being patronizing” as that might kill the mood in group events and make me look like someone who’s blowing things out of proportion. This happens a lot though, so they wouldn’t realize how frequent it is.