[exim] Exim4 condition, need help

Hi there,

I'm trying to have exim look at the sender address for all incoming
mail, if it matches more than one row (via a mysql query) then prepend
the subject with 'foo'.

I've come this far;

--
set acl_m9 = mysql;SELECT COUNT(*) FROM prospect_addresses WHERE email
LIKE '$sender_address'

if acl_m9 contains "1" then

headers add "New-Subject: [foo] ${escape:$h_subject:}"
headers remove Subject
headers add "Subject: $h_new-subject:"
headers remove New-Subject

endif
--

I'm totally unsure where to place this within my Exim 4.60 config
however, or even if I have the syntax correct (Exim syntax confuses me
much).

Could anyone lend a hand?


cheers
Michael