You could manually append something to /etc/relayhosts ............
:p
Or tweak antirelayd to continue to add the same IP in, over and over again. This is probably more possible. Just have it print the IPs in question to that file when it's putting all the authenticated pop3 users in there.
if this completely was not what you were asking, my apologies
i don't think you can assign multiple allowed host files for relaying, to exim. but then again that program can do about 831,183 more things than I've ever actually used.
