How do I route email?? smtproute??

[kayleigh]

Hi I had a spamming problem and there is a host that could not be
protected so I block all smtp traffic to that server.
Problem is that the server could not received emails, so I set qmail on
my serverA so that it will receive emails for serverB.
 
 
How do I route all emails to that serverB using qmail??
I already put a MX pointing to serverA to receive email for serverB.
Is there a way??

Thanks for being patience with me

Kayleigh