automagic memberUid in posixGroup

[Mike Sturdee <sturdee@pathwaynet.com>]

Is there an auto-magic way to have a use be listed under the posixGroup
corresponding to their main group, and removed just the same when
switching to a different group, or being removed all together? I'm doing a
set up with FreeRadius and about 10,000 users split between 5 groups
depending on their radius profile, and there are a good amount of users
that switch their profile, and it still needs to be kept nice and tidy. No
stale group info laying around.

Thanks!

-Mike