Connection two different scenes together

So i'm trying to make a dummy program that at this stage is just text on the screen. The idea is the following. Their is one main display, this will be the "Game" (probably a blue screen with some text) the second "Message" scene is a message window. I want to send a text message from one scene to the other. (later i want to send other things, but it's proof of concept)

Now i envisioned this working where the network manage sat on the "Game" scene and the "Message" scene would connect and send the data, but it could work where their is a central server, both connect and the message gets sent from "Message" to server to "Game".

I'd actually prefer to try both methods.

My question is simply: is this possible? from my experimentation, the network manager offline and online scene's seem to have to be the same on both clients, can you have a similar offline scene and once connection is made change to a specific online scene?

thanks for any assistance.