Yeah, I used to manage a Google account for a school district. I was able to disable the reply all for certain groups. My solution was to disable it for all groups except for one that I specifically created to allow it. The only members of that group had to be allowed in through a vote of our little tech committee which consisted of me and various upper level admins.

It worked quite well and it was hilarious listening to the students bitch that I had locked them out of one of the pranks they wanted to do.