postfix newbie

Hi all,

i have installed the postfix server and mysql. Mysql tables are used for
storing the information. I need to do this:

i would like for given email (dynamicaly) define the program to be
executed. For example:

when incomming email for address sdfsa@example.com run
script /var/www/scripts/email_filters/filter_a.php

Can me somebody help please ?

Thanks Miloslav Vlach