scoring crossposts

[Dale Henderson <nilram@hotpop.com>]

I'm trying to score crossposts down. I found this piece of code:

  ("xref"
   ;; the more cross posting, the exponentially worse the article
   ("^xref: \\S-+ \\S-+ \\S-+ \\S-+" -1 nil r)
   ("^xref: \\S-+ \\S-+ \\S-+ \\S-+ \\S-+" -2 nil r)
   ("^xref: \\S-+ \\S-+ \\S-+ \\S-+ \\S-+ \\S-+" -4 nil r)
   ("^xref: \\S-+ \\S-+ \\S-+ \\S-+ \\S-+ \\S-+ \\S-+" -8 nil r)
   ("^xref: \\S-+ \\S-+ \\S-+ \\S-+ \\S-+ \\S-+ \\S-+ \\S-+" -16 nil r)
   ...)

Then I noticed a massively crossposted article that wasn't
scored. When I investigated the headers, I noticed there was no Xref
header. 

So I was wondering could I score on the newsgroups header. According
to the documentation Newsgroups isn't a valid header to score on.


On another note, is there any way to check a header to see how many
times a particular regex matches and use the count to set the score. 
That is in the example above see how many times the regex \\S-+
matches the xref header and then set the score to 

(- (expt 2 (- count 3)))