You may be able to swap out the .dat file located in .\minecraft\world\players for each user. BACK UP YOUR WORLD before you attempt this. The basic solution would be to move your .dat file into a different location after you close the game and move in the other player's backed up file before they start. From the server's perspective the player would revert to a previous condition.

This link may be useful when messing with the players folder. http://minecraft.gamepedia.com/Server#Reset_player

To set this up... Start a new world Player 1: Login and play Save and quit Rename the player .dat file to include your name Player 2: (same as player 1) Player 3: (same as above)

THEN to switch users...

Player 1: Rename your .dat file to the original name. Login and Play Save and Quit Rename the player .dat file to include your name ...

You may be able to swap out the .dat file located in .\minecraft\world\players for each user. BACK UP YOUR WORLD before you attempt this. The basic solution would be to move your .dat file into a different location after you close the game and move in the other player's backed up file before they start. From the server's perspective the player would revert to a previous condition.

This link may be useful when messing with the players folder. https://minecraft.wiki/w/Server#Reset_player

To set this up... Start a new world Player 1: Login and play Save and quit Rename the player .dat file to include your name Player 2: (same as player 1) Player 3: (same as above)

THEN to switch users...

Player 1: Rename your .dat file to the original name. Login and Play Save and Quit Rename the player .dat file to include your name ...