block spam based on subject?

[Michael Masse]

Looking through the examples for the whitelist and blacklist settings in
MailScanner I see that you can pretty much do just about anything with
from and to addresses.    Is it possible to create rules based on the
subject?   We've been getting bombarded with spam that has "re: v??agra"
in the subject for the last month.    It's always changing ever so
slightly so that heuristics doesn't work so good with them, and I didn't
think they would be at it for this long to bother with making a special
rule for them, but they just keep coming and coming and if I could
simply reject any email that has the previous phrase in the subject,
life would be much happier.   I realize that making special case rules
like this isn't the best way to go, because they could simply change
something else about it tomorrow, but it would make me feel better right
now if nothing else.

Mike