[exim] How to tell Exim not to issue mailer daemons

Hello,

My Exim server acts as a virus scanner and an SMTP relay for some domains. When those remote MTA refuse emails - because they are spam for example -. Exim gets a 5xx code and so issues a MD back to the sender.

I'd like to disable mailer-daemon when Exim gets some kind of 5xx codes. Is this possible ?

Christian