exim将邮件重定向到脚本

I am looking to set up a mail relay so that any mail sent to for example

@example.com

gets parsed be a PHP script.

I know to do this for indervidual address I could do some thing like

(from the following web site http://evolt.org/incoming_mail_and_php)

Con figure an Aliases such as

script: |/our/script.php

then any emails sent to script@example.com will be passed to the script given..

but how can I make it that every email to @example.com is passed to the script? thank you