[exim] Yet another address rewrite question

Hi,

i need to do a (sender-) rewrite like explained in FAQ 801
https://github.com/Exim/exim/wiki/Q0801

*@*.your.domain $1@???

This relies on a "hardcoded" domain name; what i'd like to have is
something like this:

*@*.${domain_without_hostname} $1@${domain_without_hostname}

So my question is: how to strip off the hostname from an address (in
this case the sender) using exims build-in stuff.

No, readsocket does not count... ;-)

Christoph