Will this work?

I have a Towny server and am planning on adding Spleef. I plan on having 4 signs in the main world that you'd right-click to join the lobby which would be in a different world. I am wondering what exactly I need to be able to do this. I'm thinking Multiverse and SpleefUltimate? A problem I have is that when I try doing /world Spleef1 it gives me the Error: Hole in floor.