Menu command to post NetMail

Let me clarify - I know the features of the MP command, but how would I have
a user, who is presumably on a different message area and/or in a different
group be able to hit a command, change to the NetMail area, post the message
and (here's the kicker) return to the area in which they originally were.

Not quite as easy as one would hope.

|08---
|15Brian Davidson |09(|10Winzlo|09)
|11Sysop, |14The Down|09-|14Lo BBS

... Origin of Life? Just check my refrigerator...