[Samba] Question about Authentication

[SerpentMage (Christian Gross)]

Ok, I apologize if this question has come up.  I searched the mailing 
lists and did not find a conclusive answer.  Unless of course I am 
missing some point.

Here is what I am trying to do...

I have a domain DEV-DOMAIN.  In this domain there is the PDC X (Samba) 
and Server Y (Windows or Samba).  A client that accesses the network 
uses client machine A (Windows), which is also part of the domain.  User 
Me logs onto the domain from client machine A and is recognized by the 
PDC as User Me with Power User rights.  On Server Y a share has been 
made free with Power User rights, but not explicitly defined the user.  
When User Me logs on they want to be able to get access to the Server Y.

Exactly how would that be set up?  I understand how to setup individual 
users, create a domain and give user permissions on shares.  My question 
relates to how groups are handled across the domain.  I do not seem to 
see much documentation on this aspect (maybe I am missing something).

Could somebody enlighten me on how groups are handled?  Thanks

Christian Gross