How do you make it so you can only join a game with a teleporter and...?

How do you make it so when you can only join a game with a teleporter? for example: You are in game 1, and you are worrying how to get to the secret game without going in the teleporter You leave the game and try to join game 2, but instead you get sent to game 1 Does anyone know?

Also

how do you make it so when you say a word the brick opens example: User1: hmm, i need to say a word to open this brick User2: It is a picture of Mario, so you have to say Mario. User1: Mario The brick opens for some seconds then closes

Roblox automatically does this as long as place1 is set as Starting Place

also

for the brick one, you will need to use the Chatted event and set the parts CanCollide to false and Transparency to something like 0.5

game.Players.PlayerAdded:connect(function(player)
    player.Chatted:connect(function(msg)
        -- do stuff with msg and player
    end)
end)