Multiple nnimap folders as mail sources

[Michael Sperber <sperber@informatik.uni-tuebingen.de>]

I'm trying to do something similar to the "directory" mail-source
specifier with IMAP, but I can't figure out how.  Here's what I'm
trying to do:

I get A LOT of email, and I frequently need to access the most
important stuff on the road, when I'm only connected via a modem, and
where I possibly can't connect for long.  So I pre-sort the email into
different IMAP boxes on the server, and just read the ones I don't
need that often online via nnimap.  So far so good.

Now, for the most important groups, I'd like to download those, but in
each instance only the ones I'm specifically interested in.  Ideally,
I'd like to have a separate IMAP box serve as a mail source for an
nnml group, so I can choose which groups to update selectively.  But
it seems `mail-sources' only gives me all or nothing for IMAP, unlike,
say "directory" which reads only the files for which I'm updating mail
groups.

Is there a way to tell it that, if I want to update group nnml:foo
(and *only* then) to consult IMAP folder foo as the mail source for
that?

Any help would be much appreciated!

(Please don't give me any answers involving the agent :-) )

-- 
Cheers =8-} Mike
Friede, Völkerverständigung und überhaupt blabla