Local delivery in 2 SMTP hops

[jpsp]

Hello there,

I would like our mail to be firstly delivered 
to my organisation's DMZ (through a regular
primary MX record), and then to make it 
route to our internal network (private
IP addresses).

I think a "smtproute" that overrides the
DNS configuration might do it, but I'm
not sure.

Is this the proper way of doing it?

Thanks,
jp