How to target meeting responses with a rule?   

I'm a recent mac convert, and so far, the only thing that I can't
figure out how to do is this:

Any time I send out an invite to a meeting, I like to know who's going
to be there, so I request a response by default.  However, I don't
necessarily want 50 "Event accepted" messages to show up in my inbox.

On Outlook, I had a filter set up that would move them all to a folder
so that I could view the comments if necessary, without cluttering up
my inbox.

I can't figure out how to do this with Entourage's Tools > Rules
dialog.  Any ideas?  Maybe an AppleScript that could just be run on
all messages to check for something?

Viewing the source of the meeting responses, they seem to be in 3
different categories.

1. Outlook/Entourage response, no comments:
I can target these by looking for the Specific Header of Content-Type:
text/calendar

2. Outlook/Entourage response with comments, or iCal/AppleMail
response:
The message type is Content-Type: multipart/mixed;, and one of the
parts has a Content-Type of text/calendar.

The second type, I'm having trouble targeting with a rule.  Any
suggestions?

Thanks.

date: 9 Mar 2007 13:15:35 -0800   author:   Isaac Z. Schlueter