Teleporting all entities in an area around the player

It’s been a while since i have been on the forum now. I am making a school project in minecraft for computer class. My idea is to pull a chunk of the ground out of the ground floating in the air, with a big hole remaining. When you use the command the player also get teleported up to the island, but i want all entities to teleport up too relative to their own location. That means i want the mobs to teleport from their location just 50 blocks up

I don’t know about this game can you please send me the link to download this game.

Ok here’s the code.

Hello? is there anyone here? i would love some help.