In the Dimension Authority Mod, you will be able to use commands (as an operator) to lock/unlock dimensions. When a Dimension is locked, players will not be able to enter that dimension.
Commands:
/lockEnd : Makes players unable to go to the end
/unlockEnd : Makes players able to go to the end
/lockNether : Makes players unable to go to the nether
/unlockNether : Makes players able to go to the nether
/lockOverworld : Makes players unable to go to the overworld
/unlockOverworld : Makes players able to go to the overworld
