10.10 I have some groups that exist on user volumes that no longer exist in the system volume set. It is apparent they were just incorrectly purged off the system volume but not the user volume. How can I clean this up?

To "re-link" the user volume group, re-create the group:

:NEWGROUP name;HOMEVS=volname

To remove the group from the user volume set

:PURGEGROUP name;ONVS=volname

Now purge it from the system

:PURGEGROUP name