How to avoid Forking using c flag ?

To: procmail(_at_)Informatik(_dot_)RWTH-Aachen(_dot_)DE
Subject: How to avoid Forking using "c" flag ?
X-Newsreader: TIN [UNIX 1.3 950824BETA PL0]

Hello,

I use procmail to forward mails to 300 people depending on words in
subject ....

To do this, I have following .rc file :
(build from script ... so don't fire me about "strange" regex :-)

       :0c
        * ^Subject: \[.*CDI.* .*([0-9][0-9]|FR|RP).*\].*\<(commercial)\>
        ! user1(_at_)magic(_dot_)fr

       :0c
        * ^Subject: \[.*CDI.* .*(38).*\].*\<()\>
        ! user2(_at_)xerox(_dot_)fr

       :0c
        * ^Subject: \[.*.* .*(13|83|84|30|06|05|26|69).*\].*\<()\>
        ! user3(_at_)avignon(_dot_)pacwan(_dot_)net

.... and +/- 300 others like this ....

It works OK, but I think that it is not best thing to do because
procmail have to fork for each rule ...

I have +/- 50 message/day, so - as far as I know - it makes
50*300=15000 forks per day :-(((

I try to make each rule "non-delivering recipe" so that I do no need
"c" any more.

So I try something like :

      :0
        * ^Subject: \[.*CDI.* .*([0-9][0-9]|FR|RP).*\].*\<(commercial)\>
        { ! user1(_at_)magic(_dot_)fr }

But it does not work ... 

Does somebody could gave me another solution to make it works better
(without forking).

Thanks in advance.

-- 
Vincent Gillet                          E-mail: 
Vincent(_dot_)Gillet(_at_)inria(_dot_)fr
NIC France
INRIA-Rocquencourt Domaine de Voluceau
B.P.105 78153 Le Chesnay Cedex