Procmail recipe for "ignore-thread"

[Nunya <31210.nospam@comcast.net>]

Searched mutt-users archive for how to "ignore-thread" in Mutt.
Found http://marc.theaimsgroup.com/?l=mutt-users&m=105208920830140&w=2
Apparently you can do it with procmail.

Would this recipe work:

:0:
*  ? $FORMAIL -x References: | grep -isF -f $MAILDIR/kill
$MAILDIR/k/

I think this means: if the References matches one of the lines in "kill",
move it to =k and stop.  What do you think?

Also: If you could post a one-line .muttrc command which would pipe the 
current message to grep, pull out the message id, and append it to kill, 
I'd be thankful.

Thanks!