Do you have some database that would map arbitrary user A to the customer entity in OTRS? If the domain is the same for all users and you have no information about the relationship between incoming message from user A and customer ID B, I don't see how OTRS could do this -- it has to be able to determine the relationship somehow, and if user B is the actual customer, then they should be the one formally responsible in the database.
One thought: if your authentication source is something like Active Directory, and you have the relationships (user A is admin for user B) in AD, you could probably query AD and substitute the source of the message as if it came from user B, and add user A as a CC. Or you could set up something external to OTRS that user B could say "these are my designated proxies who can submit issues on my behalf" and check that during postmaster processing.
> -----Ursprüngliche Nachricht-----
> Von:
otrs-b...@otrs.org [mailto:
otrs-b...@otrs.org] Im Auftrag von
> Grzella, Mark
> Gesendet: Freitag, 31. Januar 2014 15:42
> An: User questions and discussions about OTRS.
> Betreff: [otrs] Postmaster Filtering -- Set CustomerID = CC Mailadress
>
> Hey all,
>
> i need an advice regarding otrs postmaster filtering.
> Task is to set the proper customer identification to the email address listed in
> CC on an inbound e-mail.
> As we are getting mails via different communication channels, we can get e-
> mails that are not directly send to otrs from the original customer but rather
> via an alternative address, for example management assistents reporting for
> a manager.
>
> Therefor it´ll be quite helpful to have the customer id not set to the e-mail
> responsible, but to the one listed in cc.
>
> I tried something like this, but with no effect at all.
> OTRS still sets customer id to its original sender, not to the cc one.
>
> Filter condition
> Headline 1 : CC << value >> (sample)
> Headline 2 : From <<value>>
myad...@mydomain.de
>
> Set E-Mail Header
> Headline 1 : X-OTRS-CustomerUser <<value>> [***]