I wasn't talking about two masters sending identical messages at the same time. But two masters...
but multiple slaves where
detected collision - plain vanilla, just sort it out
undetected collision - one slave wil get a reply, the other will 'see' it did not get it's reply.

I only use slave collisions for node allocation, of course, I have none for regular communication (save hardware failure)

Erik

I would recommend to anyone to avoid multumaster like the plague.