[wplug] Email Server?

[DK]

Hello All,

My company is working to move our email in-house.

To prove everything is working, I want to set a test server using our
domain while still allowing "normal" email to be handled by our ISP.

For example, I would have two email address:

dkraus at isquaredt.com - messages to this address are handled by our ISP
dkraus at w2.isquaredt.com - messages to this address are delivered to
our in-house test server

Is this possible?  How is the DNS configured?  Is there a better
method to accomplish this test?

Thanks,
Dave