"Bomber" in our meeting

Last night we had a divorce support meeting. usually we have 30+ people in our meetings. This has never happened (doing this for over 3 years) but there were a few people that joined that were mocking the other people as they shared their situation. We booted them and they joined with a new name. It took a while for the host to figure out who it was again before they were booted again. I've looked through all of the settings but haven't found a way to block people permanently. I did change the settings that if we are recording it will save out each person's audio so we can go back and find the people that were making the noises or mocking others. 

Any other suggestions?