[Samba] Usermap file structure question

[Sheldon, Jason]

Configuring Samba 227a on Redhat 8.0 with winbind and pam to be able to
login to the NT 4.0 domain, host a share folder, host a printer, and connect
to windows shares.

for some easy access control, I'd like to add a usermap file (is this a good
way to go?)
But I'm confused about the syntax.  If i had a domain named INFORMANT, and
an NT group named Project Users - how would I map this to local unix group
named "project".
like this?

@project = "INFORMANT+Project Users"    

is there anything else I have to put in the usermap file?  

Thanks for any info -
Jason Sheldon