Help requested setting up mail on my Debian stable system

I'm running getmail (from cron) to get mail from my various (pop)
mailboxes, putting it into my ~/Maildir from which Dovecot dishes it up to
my imap-speaking mail clients (local or remote). This gets all mail for my
domains including some for other members of my family: I want to be able
to deliver theirs to them (to be served by dovecot).

I could use procmail or maildrop to filter mail for the other users
and pass it to them - but how? Procmail's documentation advises that it is
not intended for doing this: presumably it should call an MTA (this distro
has exim installed) to deliver mail to other users.

I guess that exim will deliver to users' /var/spool/mail/ mail
spools (That's where system mail for me goes, and I fire up mutt from
time to time to check it). I need to either get exim to deliver to Maildirs
(if it can do so) or reconfigure dovecot to serve up mailspools as well
as Maildirs. From my tenuous grasp on Dovecot's documentation I think it
can do this with namespaces.

Does this sound like the right approach, and if so has anyone done
this already? Much as I value the Learning Experience of working it out
from scratch at the moment there's a pressure to Just Get It Working. I'd
particularly appreciate help with
* procmail or maildrop config to invoke exim to pass message to other user
* dovecot config to serve messages from Maildir and mail spool

John Stumbles

I'm more non-competitive than you