preserve recipient address with catchall

[mrlo...@googlemail.com]

Hello,

I have a domain where all mail is stored in a single mailbox and then
being fetched by a zarafa server via pop3. The zarafa server of course
has to be able to deliver the mails to the correct users. So I tried
adding X-Envelope-To via check_recipient_access which is working as long
as there only is one recipient.

With mulitiple recipients (to, cc and bcc fields) for each recipient
address a X-Envelope-To header is generated and the mail is delivered
once for every recipient into the catchall mailbox. Is it possible to
change this behaviour so that there is only one X-Envelope-To header in
every delivered mail?

Some more Information: I'm using amavis and tumpgreyfs and dovecot lmtp.

Any help would be appreciated,
Volker