add clientID-param to "stream" API to facilitate analytics

[nasko]

I have a front-end application which tunnels all stream-requests to Subsonic via predefined user "XYZuser". Then I use "getNowPlaying" API which unfortunately links all the history back to "XYZuser".
Question:
Is it possible to have "stream" API capture additional parameter "clientID=client123" which is later exposed accordingly by "getNowPlaying" API ? This will allow me to link playing history back to my original clients.
How much work would that be ?

Help appreciated