The way I think of it, it would be similar to how you can change channels in RTB. In blockland, you can already have multiple mini games running at once, but I always find it annoying when people that arent in your minigame are in the way/interfering. So, when you join a minigame, you could enter basically a different map so the people that arent a part of you minigame can't interact with you.
This is what you are askign for.
Not really. I mean having multiple three dimensional play areas that are linked together by the server.
Really, it comes to the basic way blockland is set up. Blockland is set up so each client is separate, but programmed to support multiple clients within the context of the mission, so why not take it out a step further and have multiple missions as well?
I think it'd require engine changes.
On the flip side, you could script a bunch of servers together and have them share chat and have portals between them. But then you'd need a bunch of servers and someone to figure the scripting all out.
I was thinking something like that too. I know how that can be done, but I'm just wondering if it really requires separate servers.