[Samba] Group mapping question

[Robert Prange]

I used the following command to set users on my samba 
server (who are part of the users group) to be able to log 
into the domain on win xp clients as Administrators.

net groupmap modify ntgroup="Domain Admins" 
unixgroup=users

I can verify this by typing "net groupmap list."  The 
other windows groups that are listed are all set to "-1" 
as I have not set them yet.  My question is, how do I undo 
the above command?

I was only fooling around with group mapping, and do not 
intend to use it.  So, I would like to set everything back 
to -1.  Also, is there a control file somewhere that holds 
the group mapping information?

Any help is appreciated, thanks.

Robert