[cobalt-security] email forwarding aliases for non-users

["Mez" <mez@xxxxxxx>]

Can someone explain in simple terms (if possible) how to create email
forwarding aliases for users not on the server.
I am using an RAQ3 and I want to be able to add forwarding addresses.

E.G.

bob@xxxxxxxxxx (domain.com is hosted on my raq3) to forward to bob@xxxxxxxxx
But user "bob" does NOT exist on my server

Is this possible at all, if so could someone point me in the right direction
for setting it up

Thanks
-John