hi silly question(world spawn point)

[mackd 0]

so somehow I managed to get a master server up and running with 2 shard worlds, and one is the caves, the other is island adventures, and somehow amazingly all this is now working, but I cannot solve an issue that whenever someone connects to the server they have basically a 30% chance of spawning in any of the 3 worlds in seems, and rather than this, I would prefer that everyone spawns in the master server. does anyone know what is causing this or how I could work it out not to do that? thanks a lot.