Killing mail according to certain header line

[pashah]

Hi,
Is it possible to make qmail send mail, containing certain header line to
/dev/null?
I am espessialy intrested in killing mail containing 'X-Spanska: Yes'
Usually this mail contains only one file infected with the Backorifice stuff.
Um asking that because I want to make it globaly for the whole host.
I`ve read through the man pages for tcpserver, it seems that it can not do
that.

any pointers are welcome.

Pashah
-- 
        http://www.spb.sitek.net/~pashah/public-key-0x97739141.pgp