Sublevels within Maptiles

Hi,

so enabled world composition and created two adjacent landscapes each having its own layer.
Now I want to use level streaming to load enemies, static meshes etc. on each map so that each map has sublevels.

Whether using level streaming volumes or loading sublevels via blueprints, I can’t find a way to actually use it.
Actors from a sublevels are always loaded (the option to change that to “Blueprints”) isn’t there. And when clicking
on the level details I get another view with no level streaming options.

What am I missing here ?