List not expanding

Ok here is the scenerio,
 
We are running exchange in the primary domain, and postfix / majordomo in the child domain.  The problem is, as I found out from the postfix group, that by trying to send an email to an address in aliase_maps or aliase_database the aliase does not get expanded to the email address unless it is for local delivery.  But since there is no local devliery the aliase does not get expanded.  I am not having the same problem with Majordomo.  Because the majordomo.aliases.db is in aliase_database and it is not delivering the email locally it is not expanding out the list.
 
Any ideas?