[Dovecot] duplicates with multiple To/CC and sieve redirect copy

Hi, In one installation we are using sieve "redirect :copy" to create copy of the incoming email (local boss gets copy of its employees mails). There is a problem when the incoming email has multiple To/CC entries with local users. Multiple copy/redirects are created (one for each employee) and there are multiple copies in "boss" account. Each of this emails has the same Message-ID.

Is there a way to detect those duplicates and discard them when saving copies into boss account?

There was a discussion on the list a while ago (Feb 10/11, 2011) mentioning this problem, but with no clear solution.

We are using Dovecot 2.0.15. Mail is delivered via LMTP (MDA/postfix is on separate machine then MAA/dovecot).

-- Adam Szpakowski