I am troubled by the fact that I cannot get Courier to replicate the mail setup
I've created via sendmail--I'm sure I'm being boneheaded about something.

The simple description of what I am trying to do is this:

(1) I want all outbound mail to "masquerade" (envelope, headers, esmtp protocol
entries, etc.) behind memeplex.com

(2) I want the local server to be memeplex.com

(3) I want all mail sent to users that don't exist on the local host to go to
the user "aathan" I don't want such mail to generate bounces or be delievered as part of an error report; I want it to show up as if
the sender got the address right.

I've tried several permutations, none of which work. The important ones are:

(A) If I set "me" to be memeplex.com, then webadmin tells me I cannot use an
"@memeplex.com: aathan" aliases entry. As a result, mail addressed to nosu...@memeplex.com bounces.

(B) If I set "me" to be memeplex.com and create the "@memeplex.com: aathan"
aliases entry by hand, courier delivers an email that reports a mail-loop when sending mail to anyu...@memeplex.com .

(C) If I set "me" to be something else, courier will identify itself incorrectly
in esmpt and email headers, and will not recognize memplex.com as a local domain. It will attempt to use the MX record for the
memeplex.com domain to deliver the mail. If the MX record points back to the same host, a mail-loop error is reported. As a
result, mail addressed to nosu...@memeplex.com is never delivered.

(D) If I set "me" to be something else, and attempt to use either the hosted or
acceptmailfor features to deliver memeplex.com mail locally, I get a mail loop.

Again, I'm guessing I've missed some boneheaded simple way to achieve my goal.
Can someone just point me in the right direction on achieving both masquerading and "deliver everything to me" functionality?

A.