[exim] Help extracting From-Address

Hi list,

we receive many E-Mails with faked From (Header), and I'm trying to
block them.
Currenty I extract the domain (most our own domain) and check it for
SPF.

Hier my code to extract the From:

warn set acl_m_from =
${extract{2}{@}{${reduce{${addresses:$h_from:}}{}{$item}}}}

Unfortunately we receive E-Mail with TWO From addresses, such:

From: Blah <blah@???> <blub@???>

and then my code does not work anymore...

Can someone help me to extract the FIRST address from the faked header?

Thanks a lot!
Luca Bertoncello
(lucabert@???)