If you do not mind having the rooms each created anew each time one is entered, then you can program each world to go to the different worlds or have actors that use the 'instanceof' keyword to determine which world is active which in turn would determine which world to proceed to. However, no matter which way you decide to go, it would take some extensive coding (probably more than in my scenarios).

Okay. Perhaps we will move on to something else, then. It's our first year of coding so I'm trying to do some projects that will let them move in different directions. I'm trying to give them a "platform" that they can build their own games on for now.

I did upload one more room changing scenario. The rooms are created anew each time the character enters them. It has a simple 'start-up' world that is basically used to hold the main character. It can be made to hold other actors or stats; or, they can be held within the main character. Anyway, the world changing code is within each world (which is more what you were looking for). You can find this scenario here. To use actor objects as portals to the different worlds would require each world to keep references to each portal object and the world 'act' method would need to call a portal method on each portal to see if the main actor is intersecting it. I will upload one final scenario to demonstrate this in the near future. EDIT: the final demo is here.