Problem with Yahoo mail server and re-sending time.

Hi,

I have a SLES10,SP1, Mail-Server and would like to know where i can change the
re-sending time to 4 hours as Yahoo wrote me back.
I got this because we send every 2 Weeks a Newsletterto our Bussiness Customers
which are registerd by us.

So how or where can i change the re-send time from the mail who are lying in the
postqueue?

Support mail from Yahoo:
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If you are seeing a 421 error code in your SMTP logs indicating that the
messages you are trying to send are "temporarily deferred due to user
complaints," this means that we have observed unusual traffic patterns
from your IP address and have been getting considerable complaints from
our users regarding emails from your server.

Please note that this is not a permanent error; your system may
automatically re-try after a while. We encourage you to try re-sending
to our emails approximately 4 hours after you encounter this error. If,
however, you are seeing this same error consistently over a 48-hour
period, we encourage you to provide us with more information so that we
can help diagnose your problem.
----

thx,
-thomas