[exim] ACL for some bounce msgs

Hi all,
my problem now is block those bounce messages coming from mailing system
that catch emails with virus that have forged sender... in this way my
users get a virus notify and every time call me worried about that...arg

what do you think abount create an ACL to block msgs wit the sender <> and
that contains the word virus in subject or in the body? Should work?

Any better solution?

Thanks

Riccardo