2 forums using same database

[trifive]

same database on differant forums
First I have 2 licenses

I have 2 differant website forum and want to use the same membership database on both forums each with differant topics etc, just that when a member joins either forum he actually becomes a member of both forums.

Last night I tried to edit the config file on the new forum so it would use the same database and it copied all the threads also to the new forum and I did not want the threadsw copied just the members is their a way to do this

Thanks

otis