[Exim] Address testing from localscan

I use a Perl script and a Perl wrapper for localscan in order to test
messages for spam, virii etc. This is done at SMTP time. I would like
to be able to do certain tests based on the final recipient of the
message, for example per-mailbox whitelists.

The problem is that I have quite a few catchall accounts and aliases that
map x@??? to y@???. If a message comes through for
x@??? the real mailbox would be y@??? so I would want to
apply the whitelist from that account. I can get the final y@???
by running `exim -bt x@???` which returns the correct answer on
the first line however it would be nice if I could do this from inside
localscan.

Is it possible to do address testing from inside localscan? I don't see
anything in local_scan.h that would do as such.

Thanks,

David