[exim] Spam with multiple recipients

Folks,

I've just seen an example of commercial spam with hundreds of recipients. It didn't attract a very high score on spamassassin so
it found its way into a lot of inboxes. Has anyone come up with a way of dealing with such messages? I'm thinking along the
lines of checking the $recipient_count variable on messages incoming to our organisation and adding a delay to the connection if
it's above a certain value. Is this feasable/desirable?

Thanks,

Clive McDowell

Information Services
The Queen's University of Belfast