Ability to disable natural regeneration

Hi, i'm on Xbox's bedrock edition of minecraft and i'm making an adventure map and after beating the map on hard you get access to a key and taking that key back to the spawn where you set the difficulty. There's a door that needs that key and it brings you to a new difficulty mode, Hardcore natural, regen off, but... There's no way of turning it off with commands/command blocks in general and requires, it to be off! you could disable it by going thru the menus. But i want it with commands/command blocks! Please add it to the game, it's the ONLY way to make that mode to work! I could make the map always have natural regen off, but the problem with that is... easy, normal, and hard (not hardcore) require it to be on.