The current system only allows for one minigame per BLID. This is because Slayer uses BLIDs to tell what items/vehicles/etc belong to each minigame, and if there were multiple minigames with the same BLID it would cause problems.
If you want to create an additional minigame, you'll need a second BLID. This could change in the future, but for now you can just get a friend to create the second minigame or use an alt.
Fyi, the bricks of the player that created each minigame are the ones it uses.
