That's a tough one! I tried a google search:
Code:
group site:freebsd.org
And came up with FreeBSD user groups all over the world! Not exactly what you were looking for, I guess.
However, I found a couple of links dealing with the operator and wheel groups:
http://lists.freebsd.org/pipermail/f...er/138652.html
and
http://lists.freebsd.org/pipermail/f...er/001724.html
For the rest of the groups, I have no idea.
I guess you have read chapter 13.8 of the handbook, which doesn't answer your question either.
http://www.freebsd.org/doc/en_US.ISO...rs-groups.html