Sieve Server-Wide

[Lee]

Hey All,
I've setup spamassassin / amavisd-new  to tag spam with an X-Spam 
header. I want to now tell cyrus to filter those emails into the users 
spam folder. I found a sieve script that does this, but I'm wondering 
if there is a way to apply the script to all users on the server. Is 
there some sort of "shared" or "default" sieve user/directory that 
affects all users or some way to have all users' sieve dir simply be a 
single directory?

Thanks,
Lee