Shadow is being casted between 2 floors | How to limit shadow cast distance/How to block shadows

I have 2 storeys, where the bottom one is directly under the top one. I do not want the top storey to cast shadow on the bottom one but I want both of them to receive directional light.

That was accomplished by setting Cast Shadows on the floor of the top storey to false. The issue now is, that if there are any objects on the top storey, the shadow is being casted on its floor, but also on the floor of the bottom storey.

On the picture below, in the top left corner there’s a character that is casting shadow on both top and bottom storey.

Is there any way how I can remove this shadow casting on the bottom storey? Or is there a way how I can set up maximum height that shadows can be casted from? Anything just to remove this ugly effect!

In the end I want both storeys to receive directional sunlight, but I don’t want any shadows from top storey being projected to the bottom storey also…

Reference picture: