[Exim] panic when delivering to multiple recipients from a f…

I've got a system wide mail-filter applied to both incoming and outgoing
mail, which is as follows:

# Exim filter
if error_message then finish endif
if $message_headers matches "X-Scanner.*et\.byu\.edu" then
deliver ${recipients}
else
pipe "/opt/infl.new/inflex ${primary_hostname} ${recipients} ${reply_address}"
endif

It works great, except when ${recipients} has two or more addresses, and
then exim panics with this in the log:

2003-06-10 17:26:00 19PsV6-0000Pv-QJ Error in system filter: malformed
address "AAA@???, BBB@???" in filter file: malformed
address: , BBB@??? may not follow AAA@???

So I've worked around this by having the inflex script perform a
separate delivery for each recipient. Is there a better way to do this,
to have the filter handle the multiple recipients itself?

--
Soren Harward
soren@???