[vchkpw] SpamAssassin, Vpopmail, conditional handling on Spam Score?

[Dave Richardson - Lists]

I'm running the QMAILQUEUE patch with SpamAssassin into Vpopmail with 
Mysql and Courier.

I'm running SpamAssassin with spam threashold "required_hits" = 8.

I allow direct delivery to the mailbox, but it is subject prefixed 
"[SPAM]"  (thus it is Spam Tagged)

What I'd like to do is add another "threashold" (probably in SA?) where 
the spam score of >15 is sent to /dev/null.  Scores from 7-14.99 are 
spam tagged (and delivered) and scores less than 7 are not spam tagged. 
(I've been seeing spam scores as high as 28.8 recently BTW)

Is there a "normal" way to do this?
D.