Milter-greylist

Hi, all -

With so many organizations using mail services like Google and Microsoft
and Amazon and the like, I am seeing more and more messages being
delayed by greylisting for *every* e-mail.

I had a mail conversation with someone today. They use some Amazon
hosted mail service. The first email came from [sender1] and was relayed
through ec2-54-153-11-11.us-west-1.compute.amazonaws.com. The second
mail came from [sender1] but from
ec2-54-153-22-22.us-west-1.compute.amazonaws.com, and so on. Every new
e-mail wound up coming through a different relay on Amazon.

What winds up happening is, EVERY new e-mail is delayed, often times
several hours because they don't retry in a timely fashion.

I'm definitely not a milter-greylist expert. Is there something I'm
missing? This is becoming more and more of a hassle every day.

Thanks!
Thomas