I just took a look at your forum. You have way too many members to set up two groups.
I noticed your comments on your forum about the trouble you are having.
My suggestion is to add regular moderators to your forum. You obviously have used a moderator in the past. Add a couple of people you know and trust to be full-time moderators.They must be people who visit your forum several times a day. Give them access control to Edit/Delete and instructions to eliminate a troll's post as soon as it appears.
Suggest you post something like the statement below, when you introduce your new moderators:
Forum pests /trouble makers are called "Trolls". Unfortunately,we occasionally have trolls.
Trolls get their "kicks' from seeing responses to their posts. Trolls don't care whether the responses are negative or positive. The more people response to trolls,the more trolls are encouraged to continue.
From now on,all posts by trolls will be immediately deleted my myself or one of our new moderators. Also, all responses to a troll's message (or name) will be deleted.Please, completely ignore the troll.
If at some future time the troll decides to post in an acceptable manner,we will consider allowing him/her to begin posting again.
Your cooperation is appreciated.Thank you.
Barry,I dealt with a serious troll problem earlier this year. The troll was posting many dozens of proxy-aided taunting messages a day.The whole forum became feed-up with the troll. It got so bad that I "Deputized" 20 forum members to be moderators,and give them instructions to immediately delete any post by the troll. Eventually, he gave up,apologized and asked for permission to begin posting again. After discussing the situation with my main moderator,we allowed him back in our forum I then removed the moderator privileges of the deputies.After all that,I now have groups set up,just in case he goes rogue again.