Multiple maps in server... :/

Hello, I’m somewhat nearing the end of the major part of my project but Im facing an issue with map loading… Allow me to explain my situation.

I’m making a game that has a HUB level that has shops, Portals and all that good stuff… The issue is when a Client trys to go through a portal into a mini games level it moves all players to that level… What I am looking for is all players to start in the HUB level then if one client goes though Minigames_01 portal he goes alone but then another client decides he want to go there to and he goes through Minigames_01 portal he will join the current other player in that world while all other clients are still messing around in the HUB… Not sure if this is do able or not but its really what im after…

Below I’ve drawn an image kinda showing what im trying to achieve… The server has 14 online players, Central HUB has 1 player in it the rest of the other players are in different levels… Is this do able?