Multilevel Networking, One Server

Hey There,

I'm trying to build a Multiplayer-Based game with multiple Levels which can be entered any time. But I don't want to use multiple Servers. So I have thought of using on "Master Server", simply a real Server (Network.isServer true...). The for each Level there connects a client which is authorative for that level. Every Client Connects to the "Master Server" and gets asigned to the correct World Server, which are still clients in reality.

How can I do it, so that the "Master Server" does not have to have a copy of all Levels running and also doesn't get copies of every Network.Instantiate, but still the Data is relayed to the correct clients with new clients getting the previeously instantiated Objects when they are supposed to?

And: Client Menu, MasterServer and World-Authoratice-Client all have different Scenes. The communicatiuon between eacht party is working, I only use RPCs there. But: Can I use State synchronization with this system?

Please tell me...