[plug] Exim/Postfix Multiple SMTP Relays

[Timothy White]

I'm looking at setting up Exim or Postfix on my server. (Currently
Postfix is on it IIRC, I've used exim before though.)
What I plan on having is each user's emails get downloaded via
fetchmail from their gmail and other pop accounts. They access their
emails via imap, and send emails via the local SMTP server.
What I'd ideally like though is to use the Gmail SMTP server from the
outgoing relay, but it needs authentication. So basiclly I want the
client's to authenticate to my local SMTP server, which in turn gets
their gmail credentials from somewhere (home dir? sameplace as
fetchmail?) and then sends there emails using the Gmail SMTP server
but authenticated as the user.
It's on dialup so obviously it can only send the emails onto Gmail
when ppp0 has come up so the queue basically is frozen until the ip-up
script runs to activate the queue runner for outgoing mail.

Is this possible or am I hoping to much? I really don't want to do the
remote delivery my self, cause if I use the gmail smtp server's it
means all sent mail appears in there sent mail box on gmail, so
basically their Gmail account and local account are synchronised
(other than folder structure.)

Thanks

Tim