[Exim] user filter file

I have a .forward file which is a very simple a list of a dozen or so
email addresses to distribute messages to.

in the format:
address 1
address 2
address 3
etc ..

Now I'd like to convert this to a filter/forward file where I have a
particular condition pipe to a program, else just forward as usual.

So the file must now contain:
# Exim filter
if $h_subject: begins "SPECIAL HEADER"
   then pipe "special_job.sh"
        finish
endif

..
forward to the usual

------

Will I *now* need to convert all my usual addresses to

deliver address 1
deliver address 2
deliver address 3
deliver etc ..

because of the change from a simple .forward file to a filter?
Or is there a better/simpler/more accurate way of doing this?
--
Jim Pazarena    mailto:paz@qcislands.net
                http://www.qcislands.net/paz