Is there a way to automatically create and fill sublevels?

I’m experimenting to create planets or at least something similiar with my limited knowledge. The last thing that came to my mind was to create a chunks of a planet in blender and put each in its own sublevel with a proper trigger volume to load and unload the corresponding chunk, but i don’t have a powerful machine so i end up needing many chunks to not use too much memory.
edit: replace “put one” for “put each”