[Samba] access to samba dir's without acl's

[ipguy]

hi all
I have a stupid newbie question...
but some background first.
I compiled samba "--with-utmp --with-msdfs --with-winbind" as a domain
member server to migrate our file server from NT
the samba server was joined to the domain
winbind is working as expected, authenticating users via the PDC (NT4)
I have created some folders on the Linux filesystem with "chmod 777" access.
the domain users can transparently log into the samber server and access the
dir's/files
so here is my question....
how do I manipulate the samba filesystem to insure that only some users have
access to dir's while others do NOT.
example.... I have a list on "domain admins" that I want to allow access to
particular dir on the samba filesystem
how do I insure that only the "domain admins" are allowed in ?
I understand that I need to change group perms for the dir in question but
is there a tool that allows me to do this quickly ?
please keep in mind that I do not have ACL support.

-ipguy