[Dovecot] Duplicate suppression from remote lists?

[Adam Seering]

Hi,
	I have a setup where users on my server who are subscribed to several 
lists on a (remote) weirdly-configured listserver are getting many 
duplicate e-mails.  I know why this is happening; but I don't have 
control over that listserver so I can't fix it.  Is there a way for me 
to suppress duplicates from within Dovecot?  The duplicates do all have 
the same (otherwise-unique) message ID.

	"dovecot --version" gives 1.0.rc15.  I'm using exim for SMTP.  I'm also 
using dovecot-lda, with the Sieve plugin.  There's a rather old thread 
on this list that mentions that dovecot-lda+Sieve should be able to 
suppress duplicates; it's not doing so automagically, though...

Thanks,
Adam