samba - Aug 2006 - authentication across 2 samba servers

I have 2 samba servers, archives3 (10.8.2.2) and roark (10.8.2.3).  
roark is the domain master.  Users on roark are in 
/etc/samba/smbpasswd.  I'd like the users on roark to access a share on 
archives3 (\\archives3\pubinfo).  How can I have archives3 authenticate 
the users against the users in smbpasswd on roark?