[exim] Preventing TXT lookups after successful acl modifier …

Whenever a DNSBL query matches, exim requests a TXT record for
the same lookup domain name in order to get the info usually describing
the reason for this entry being in a particular list.

Is there anyway to prevent this? Thereby significantly reducing the
number of DNS requests? I am generating my own response messages, so
the info just gets thrown away...

     Thomas