[Exim] Unusual need

I currently have a router as follows:


company1_domains:
driver = domainlist
route_file = /etc/exim/company1.domains
domains = lsearch;/etc/exim/company1.domains
search_type = lsearch
transport = remote_smtp


I would like to add another router before this one, to catch any
message to a few specific local parts, and reroute/forward it to
postmaster@??? instead of where it was originally going..

Easy to do this with directors, but not sure how with routers. (There
are non-local domains. I could make them local domains if I could get a
director that accomplished the equivalent of the above router)                     

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