i need expert in unity3d multiplayer

I need someone to develop the framework for my game. it's a multiplayer metaverse where each user can log in and after they log in they get their land id from the server which is assigned to them by the admin dashboard. once they log in they can build on their land and only their land the other users' land can only view and not built on it. The Admin dashboard has multiple clients each client can have multiple users. so the client can create ids for the users in the metaverse. once the client creates the ID the user can download the application and login with the provided id. once they log in they will see the metaverse that belongs to there group or client. I need help in designing the framework for this the visuals and 3d models will take care of it. from your side, we will need the login framework and serverside setup for this metaverse.