[Exim] exchange and multidrop

Hello,

a dozen users do POP3 to get their personal mail. A copy of their mail is
in a multidrop-account. The latter is handled by MS exchange via some sort
of POP3 add-on.

Now, if a mail is sent to a couple of persons, with the above twelve among
those recipients, those twelve users don't get the mail twice (as
expected) but twelve times.

The exchange admin says exim does not process the messages properly.

Is that true? The copies are delivered as duplicats - I use mysql to map
between local parts and mailboxes. Am I missing special tweaks needed when
dealing with multidrop accounts or is it an exchange problem?

TIA,
Volker

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