How do you allow different playernames on the same computer user account access each other's saved worlds?

To clarify, this is NOT a multiplayer game. I like using alts to do things in different places in the same world; for example, one alt living in the world spawn, another alt exploring the nether, another in the end, yet another exploring thousands of blocks away, and another one working on a build several thousand blocks in the other direction, etc.

I reinstalled Education Edition recently and found out I can't do that anymore on the default settings. How do I change it back so I can get my alts to access the same world again?