[Exim] headers_add & headers_remove with unseen routers

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Hi,

I'm running Exim 4.22. I have a setup whereby local e-mail is delivered to two places - one for the user to collect and one for server-side backup. One of the routers is for groups, and collects mail for group address (eg group@???) and devlivers it to a list (eg user1@???, user2@??? etc). The group router removes the reply-to header and adds one which has the group address in it, so that replies go back to the whole group. The problem is that the new reply-to header is lost in the duplicated message produced by the "backup" router, which runs "unseen". I need the "backup" router to run on every address after redirection so that everyone in the group gets a copy of group mail in their backup files.

Is there an accepted method for preserving modified headers through unseen routers? If not, what's the best way to get round it?

Regards,

Andrew Hutson
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