[Samba] Complex [homes] rule

[David Markey]

Hi All 
Im my [homes] share i want to have two access rules. First one is
%D%w%S so that DOMAINdmarkey will only be able to access his own home
directory and nobody elses 
But I only want users in the postgrad group to be able to access
their home directory. 

How could i implement both rules on the [homes] share? 
Example: %D%w%S AND @DOMAINPostgrad 
Any Ideas? 
Thanks.