[Mimedefang] Relayed through...

[Ashley M. Kirchner]

    I'm faced with a bit of a problem here with two large domains, 
namely amazon.com and ebay.com/paypal.com.  Let starts with Amazon 
first:  When I send say a 10% discount to someone else, Amazon will 
create a message with my From: address to the recipient's address and 
said message will get relayed through their servers.  However, MD, or 
more precise, SpamAssassin will block such messages due to several spam 
rules being matched.  Essentially the same thing happens with eBay as 
well.  When you win an auction on eBay, PayPal will send you an email 
with the From: address being the address of the person that held the 
auction and it gets relayed through their servers.  Once again, 
SpamAssassin will dutifully block these messages because of spam rules 
being matched again.  (With eBay it's even humorous.  The message 
subject will say 'Congratulations, you have won [whatever auction]' - 
and SpamAssassin translates that into 'Congratulations, you have been 
scammed!' - quite funny.)

    So my question is this, is there some way in MD that I can somehow 
"approve" these messages and bypass SpamAssassin all together?  Maybe by 
looking at the relay from address/IP and let it through?  I'm not aware 
of any of these two domains being used as a spam relay in the past, so I 
can't think of any reason not to do that.