[exim] handling Yahoo

Hello,

Since yesterday I have been practically unable to deliver emails to
yahoo.* accoutns. I have about 2000 emails now in queue, most of them
destined to yahoo.

The problem is the sheer number of emails I need to deliver. When there
are only few emails in queue, yahoo greylists them and most get delivered
with a subsequent queue run. Unfortunately, when the load gets bigger,
yahoo flatly refuses connections (but most likely does it at a firewall
and not MTA level because I do not see any specific 550 errors, just
something like:

2006-11-03 10:19:51 1Gfjf4-000HNf-1c == ADDRESS@??? R=dnslookup
T=remote_smtp defer (-53): retry time not reached for any host)

Now, when I turn off exim and do manual deliveries (exim -d -M <message
id>), I am able to send a few emails, a few more get greylisted. Then I
take the one which was greylisted, do a manual delivery again and so on,
so forth. Obviously I cannot continue like that. Is there something that I
can do in exim to limit deliveries to only a few addresses per queue run
and per domain? Would that make sense? But then will that remove the many
emails from queue? I guess not. Any thoughts?

I am a bit desperate and will appreciate any comments/advice you can give
me.

Thank you!

--
Zbigniew Szalbot