Spawing in the Nether

I have always liked the idea of trying to spawn in the nether and then trying to get out into the overworld, but minecraft has never allowed it as world spawn is restricted to only the overworld. I think we should be able to set spawn anywhere to allow fun alternate ways to play the game. While you can just open a portal to get there, I own a realm and want to make a world where the nether is set as world spawn, and getting all the players to just "obey the rules" isn't going to work. Some will still collect things from the overworld before joining, and that will mess with the escape process for everyone else. I also tried blocking off spawn with bedrock and putting a portal inside and it just moved spawn somewhere else. I even tried using command blocks and they still wouldn't work. Me and everyone in my realm would really appreciate it if you can add an option to spawn in the nether. Thankyou.