Mail Routing question

[david . heydari]

Hi Everybody,

We use qmail as a mail gateway on two different boxes, one for incoming mail
(incomingmail.foo.com),
and one for outgonig mail "outgoingmail.foo.com". All incoming mail at
"incomingmail.foo.com" sends 
to the internal networks, and there is no users account on the
"incomingmail.foo.com", 
the file "smtproutes"  looks like this:
SubDomain1.foo.com:SomeMailserver.foo.com
SubDomain2.foo.com:AnotherMailserver.foo.com
foo.com:internal_mailserver.foo.com
and so on... 

The question is: How kan i route incoming mail per user basis, i.e. mail for
"[EMAIL PROTECTED]" should go
to say "[EMAIL PROTECTED]"

Best regards
David Heydari