[Exim] How to be able to send an pesonnalized email to all e…

Hi,
I want to create a system filter which would send one email to each email
address in the $recipients list.
For each email created, I want to be able to modify this one with a
variable.
Explaination :
Exim receive an email with two emails in the recepients list :
userOne@??? and userTwo@???
This mail has a particular subject like "multirecipient"
For each emails in the list, I want to send the normal email plus send
another email with a personnalized text (which is different for the two
email)
But I'm unable to do that. Until now all I was able is to send a
personnalized email to the first email address in the $recipients variable
with the following system filter :

if $header_subject: contain "multirecipient"
then
  if foranyaddress $recipients ( $thisaddress contains "@domain.example" )
  then
     mail to $thisaddress
     from postmaster@???
     subject "multirecipient mail ${thisaddress}"
     text "thisaddress = [${thisaddress}]\n\
     --------------------------------------"

     logfile /var/log/exim/filter.log
     logwrite "$tod_log Mail for multirecipient arrived. Recipient list :
$recipients"
  endif
endif

With this rule, userOne will receive the normal email plus a email with a
personnalized subject ("multirecipient userOne@???"). But userTwo
will only received the normal email.

How to be able to send an pesonnalized email to all emails in $recepients?

Thanks

Regards

Jean-Robert Wiame
Belgium