[Exim] Rewriting all recipient addresses from a given host

Hi folks,

I want all messages from a given host to be delivered into a single
local mailbox, regardless of the recipients provided by the remote host
during the SMTP session.

Straight rewrite rules in the rewrites section don't seem to be what I
want.

What should I read? I've tried the FAQ and have skimmed the filter
specification and the manual section on rewrites. I think my answer
lies somewhere in one of these two?

Ciao,
Sheldon.