[exim] Regular expressions from file for match{

In the MIME ACL, I'd like to be able to block attachments which
match regular expressions. So far I have something like this:

  deny
    condition   = ${if match{${lc:$mime_filename}}{\\..+\\.}{yes}{no}}
    message     = This message contains a prohibited attachment filename ($mime_filename)
    log_message = DENY: attachment filename ($mime_filename) matches RE

Is it possible have a single condition retrieve a list of RE to be matched
from a file? I've tried all sorts of lsearch incantations, but cannot
get it to work. I'd like an external administrator to be able to maintain
that list, w/o having to modify Exim's configuration.

Any ideas?

    -JP