how do you use a deferral host in qmail?

[Jeremy Hansen]

I'm wondering if it's possible to setup a deferral host in qmail?  If a
message gets deferred, then the mail goes to another machine in charge of
just retrying deferred messages instead of clogging up the main mailer
machine.

Someone told me this is possible to do in sendmail.  I haven't used
sendmail in years so I don't know first hand, but it's been my impression
that qmail can do anything sendmail can do.

Thanks
-jeremy