A more user-interface style would be to have buttons on the wall with signs above them that say things like "Level 2" or "Second Floor: Storage" and command blocks behind them or activated by a /testforblock command that have /tp commands such as
>/tp @p x y z

>/tp @a[team=Elevator] x y z

>/tp @a[r=2] x y z

I used this system very much when i was building my first command block world called "Megatropolis". It involved players exploring a vast city and trading with villagers to get title deeds, keys and coins. When using this a lot on structures with evenly spaced elevators, copied commands and relative coordinates sped up programming signifgantly.