Turn based game server instances

We are building a mobile turn based 1v1 puzzle game (similar to Wordfeud but with a bit of unity physics). It seems like we need to use an authoritative server in order to prevent cheating and discrepancies in the physics calculations on the clients.

What kind of network topology or pattern is there for us to use? Today, we are using Parse.com to store the game data for each match. This is working really smooth, but as I said, we might be forced to use an authoritative server to calculate the physics for each match (which is a bummer, but seems understandable).

I'm exploring the possibility of using a lobby server that matches players and when two players are paired together for a match, the lobby server creates a new instance of the game server. This new instance contains the scene where the two players are playing against each other.

Is this a usable approach? Might it even be scalable? We are desperate for a networking approach thats can fit our needs.