Duplicate message filtering

I'm using the recipe below to filter duplicate messages, however if a
message is addressed to both me and the procmail users list, the message
addressed to me arrives first, and is not routed to the "procmail-list"
folder.

So how do I ensure messages end up in the appropriate list folder while
filtering out duplicates?

Sample header:

To: creelan(_at_)orst(_dot_)edu
Cc: procmail(_at_)Lists(_dot_)RWTH-Aachen(_dot_)DE

Recipe:

# weed out duplicates
:0 Whc: msgid.lock
| formail -D 8192 $PMDIR/msgid.cache
:0 a:
$DELETE

# procmail users list:
:0 :
* ^Sender: procmail
procmail-list


Thanks,

Tyler

On Sat, 16 Nov 2002, Fred Morris wrote:

> >      -I"Content-Type: text/plain"
>       -I"Content-Type: text/plain"\
>
> > Fred Morris
> > m3047(_at_)inwa(_dot_)net
>
>
> _______________________________________________
> procmail mailing list
> procmail(_at_)lists(_dot_)RWTH-Aachen(_dot_)DE
> http://MailMan.RWTH-Aachen.DE/mailman/listinfo/procmail

_______________________________________________
procmail mailing list
procmail(_at_)lists(_dot_)RWTH-Aachen(_dot_)DE
http://MailMan.RWTH-Aachen.DE/mailman/listinfo/procmail