[exim] How can I customize exim mailer

Hello,

My client wants me to setup exim so that if there are a particular bounce
reason such as "yahoo TS03 permanent block" exim should stop sending mails
to that ISP until the situation is back, which usually is after 48 hours.

I have no clue how to do that in exim. Do I have to custom program exim and
recompile it? any ideas what we are talking about here?

Give me some clues please.

Khurram