Not to muddy the water, but I have confirmed that this "FILTER" method in fact does not work as one would expect. A COMPUTER object also has a field for USER, so this type of query actually returns the names of computers as well if found in a container with user accounts.

Mark,
If you can give us the name of your groups and your domain we may be able to supply code that will return what it is you're looking for.
Are you running KiXtart 4.22 ? Are you a Domain Admin or OU Admin?