Not exactly, one server is one IP. You can still run multiple processes, of your project, on different ports. And you can have multiple ports per process.
With each process you will have a some overhead, like memory and processing, so i would definitely want to see what that cost is before i would make a decision, if you just separated your lobbies by processes it would be really simple. You wouldn’t have to worry about other worlds and you wouldn’t have to manage network visibility. Very simple.
But if the overhead cost of running separate processes becomes too high, you could still try and make a server handle multiple isolated rooms in one process. However complicated that would be.