Sketchup to Unreal: walls fused together issue

Hello! Totally new to the forum here, and self-taught at Sketchup and Unreal so it’s very likely I’m doing beginner mistakes.
My issues is that wen I export a Sketchup model to Unreal Engine, I can hide or unhide all the objects separately, except for my floors and walls: they seem to be glued together; so when I toggle a wall off, all walls, as well as the floor, get hidden.
In Sketchup I can hide each wall and floor part individually.
How could I make sure to only hide1 wall off my model rather than all of them at once in Unreal?

I am on Sketchup Pro 2022 and Unreal Engine 5.3.2.

Many thanks for any help


–>sketchup with wall visible


–>sketchup with wall hidden


–>unreal with wall visible


->unreal when I try hiding the wall (clicking the wall selects the whole model so the whole model gets hidden, leaving only the textures)