[Samba] Group file ownership...

[Brad]

We have a Red Hat 7.3 file server that serves about 30 Windows PCs via Samba 
2.2.3a.

I have one group called "users" that everyone is in but when a file is created 
by a PC, the group ownership on the created file is not "users", but the same 
as the file owner name. Is there any way to force the group ownership of 
created files?

Also, is there any way to force file ownersip to a given user on newly created 
files?

Regards,
Brad