Minecraft – How to teleport all players from a specific world into another world

Information taken from the wiki:
http://minecraft.gamepedia.com/Scoreboard#Teams

To teleport players in specific teams, simply add the team=[name] filter onto the @p command, resulting in:

/tp @a[r=10,team=red] 100 100 -100

Just note that everything is CaSe SeNsItIvE (Case sensitive). It means that 'red' is different to 'Red'. Replace the word 'red' with the name of the team.

To set make team, use
/scoreboard teams add [name] [display name... (This can be more than one word)]

And to add a player to the team, use
/scoreboard teams join [team] [player]

The /tp command accepts relative arguments (~), but you won't be able to do it in a single command. You may wish to use a pair of command blocks to execute them quickly and more or less seamlessly.

The following will teleport Steve to Joe, then zero blocks forward (in the x direction), fifty blocks up (in the y direction), and zero blocks to the side (in the z direction).

/tp Steve Joe
/tp Steve ~ ~50 ~

The format is as follows:

 /tp [player] <x> <y> <z> [<y-rot> <x-rot>]

More information can be found on the Official Minecraft wiki: http://minecraft.gamepedia.com/Commands#teleport