I have not done due to ignorance.  Thanks for the info, I'll look into it.

Adding the queue name to an X-Whups-Queue header makes sense. But in 
your case, why don't you simply create aliases (or cronjobs) for all 
queue addresses to use mail-filter.php?

When whups sends me emails now, subjects look something like this:



[Tickets #101] Re: kersey picklist problems



We are small organization with 4 queue's setup.  The preference is to 
have everyone receive updates on all tickets.  Right now, the queue's 
owner email is "sender" of an ticket update.  My mail client organizes 
this locally into respective folder.  If I turned on the reply to 
email feature, my understand is that a special email account must be 
create for horde to monitor and process replies.  If I switch to a 
unified sender email address, I will no longer be able to filter off 
sender email address.  There is also currently no other info in whups 
email notification header that I can use to filter off of in regards 
to queue identification.  Such a thing could be accomplished with 
either modifying generated subject line, or inserting a custom mail 
header(not really sure if standard compliant).

Why would you need the queue name in the subject for that?

It may be a better solution to tag whup notification emails with the 
originating queue name.  This way, you can turn on the email reply to 
ticket feature, and still use a mail clients-side filter to organize 
email sent from whups notification.