[Exim] Is it possible for forwarders to filter tagged spam?

Hi all,

I am using SpamAssassin with Exim. Is it possible to set it up so that when
a forwarder forwards the e-mail
to a remote e-mail account, it doesn't forward the e-mail that has been
already tagged as spam by SpamAssassin?
The tagged spam usually has a subject begins with *****Spam****.

Thank you.

Shuai Liu