[Serusers] Anyone doing something to handle RFC3326?

We've been looking recently at RFC 3326 (Reason header fields for SIP) primarily to help with logging in some of our UAs. While I know that SER can essentially tack on any header anywhere, I'm wondering if anyone's come up with a solution for handling something like the Call Completed Elsewhere reason tag: Reason: SIP ;cause=200 ;text="Call completed elsewhere" Essentially, this would be sent in a CANCEL message to all clients that did NOT pick up the SIP call. Since SER forks off a separate INVITE to any contact in the location table matching the intended recipient, it would be nice to fire off a reason for a cancel to some UAs which would then know not to bother logging a call as 'missed' in the case of another phone picking it up. I'm sure there's a way to hack this using the current functionality (or if not, a slight modification of current functionality), but if anyone's done it and has a code snippet, that would make life easier. N.