Disconnect treatment modification

What I am attempting to do is playback a message to the remaining party after another party disconnects. Here is an example:

During a call between my cell phone and a sip phone in my house behind asterisk I hang up on my cell. What I would like to do is playback a message to the sip phone before sending the BYE.

I tried

and this attempts to playback the message to the disconnect initiator instead of the remaining party.

How can I tell asterisk to playback a file to the remaining party BEFORE sending the BYE?