Filter email from specific sender to out of my domain in Postfix

Hi,

I', trying to redirect to my account the mails sended by an specific account but only if these emails are going to account out of my domain.

Which is the best way for doing this?

I tried with header_checks but it's not possible because it processes one header at a time.

Thanks

 

Maybe you can do this with a Postfix filter:
http://www.postfix.org/FILTER_README.html
http://www.postfix.org/SMTPD_PROXY_README.html