sharing inventory

when you create a world u can add on a cheat like keep inventory but now u can share ur inventory.When i start the world your inventory is x times bigger for the amount of people ur playing in the world. So ur playing with another person ur inventory is 2 x bigger than normal,2 people 3x bigger etc . and if someone dosent want to share ther inventory then can switch it off in the settings. then when u share ur inventory with someone when u mine wood or something it appears in both inventory,and if u place something down or in a chest it disappears in both of the inventory.