[Exim] spam filer and users.

Hello. Beforehand I am sorry for my bad English.
So, I create a mail server based on the web-interface. I write php scripts... I have a one quastion:
I should create a mail spam-filter now. We shall assume, that to the user goes spam and he needs to block spamer address. How to do it? I, certainly, can make a script on php which will be block evil spamer, but
it will be locked spammer not to the concrete user, and all mail server as a whole. How to make blocking to the single user not at all mail users?

One more time, sorry for my english.

--"The Securities Market Magazine" Inc.
With best regards,
Dennis S.Davidoff (System Administrator).

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