[Exim] Loop over Header data in system filter

Hello,

in a system filter is it possible to write a loop over
addresses in To: and Cc: headers?

Like:

for any address in $h_to:,$h_cc:
do
add 1 to n1
done

so that $n1 has got the number of addresses in the To: and
Cc: headers after the end?

I need this number of addresses. Or can I get it on an
other way? I do not mean $recipients_count, because this
is only the numer of (real) recipients of the envelope,
but I really want to count addresses in To: and Cc: headers.

Thanks,
.\ndreas