[Exim] ACL help?

I currently have the following to enable pop-before-smtp for some clients
that does not support autehticated SMTP

hostlist relay_from_hosts =
127.0.0.1:82.182.108.36:net-lsearch;/tmp/exact/relay

Now, since i only want to enable this for a certain few accounts, can
someone help me come up with a clever ACL that would relay for the IP's in
the "relay" file only if the "from"-adress of the mail is in another list?