Using Spine for scaling a room across multiple servers

The idea is to forward a stream from one room to another room using Spine. Then, regarding to this conversation, we would be able to scale a room by creating two or more rooms over different servers and forwarding streams between them.

By a little customizing Spine code I could subscribe to the stream in room-A and then re-publish it through room-B but no real data is transmitted. I guess the subscribed/published stream by Spine is not a real stream that carries media, right? At least the documentation says that:

Client API
Note that you can not publish/subscribe streams with video and/or audio. We are working on this feature in order to develop another way of distribute video/audio streams."

Now my question is that what are publishConfig.video.file and subscribeConfig.video.recording for in the “spineClientsConfig.json” file if we can not have audio/video in Spine? I’m just confused.

Any body can enlighten me?