Exim - Mail Filter, Blind Copy All Domain Emails

I have Exim install on my server, I have a few filters setup.

I have several domains on the same server.

What I want to be able to do is blind copy all emails SENT and RECEIVED from *@domain1.com delivered to backup@backup.com

Here is my filter that copies all incoming mail, (THIS WORKS 100%)

PHP Code:

if error_message then finish endif 
if $header_to: contains "@domain1.com"
then unseen deliver "backup@backup.com" endif 

Now this filter does NOT work, I want it to blind copy all emails sent from *@domain1.com

PHP Code:

if $sender_address contains "@domain1.com"
then unseen deliver "backup@backup.com" endif 

I have 1 outgoing mail filer working, however it is for a specific email address, here it is....

PHP Code:

if $sender_address is "user1@domain1.com" 
then unseen deliver "backup@backup.com" endif