solid difference problem

Hi,
I'm new to grasshopper so sorry in advance if this is a silly question.
I'm trying to make a hollow structure out of a Voronoi cell and cut a gap facing the center of the Voronoi cell for one of it's sides.
I have already done the structure of the side of the Voronoi cell that contains the gap. i did it using sweep, spheres, solid difference and mesh thicken. (panel 01.jpg)
For the other sides of the cell i don't need them to have a gap, i just need them to be hollow
i tried solid difference again, but for some reason if i make three pipes cut one sphere the result only shows two out of the three pipes being applied to the sphere. i also tried using solid difference with one pipe at a time for the same sphere but that didn't work. (solid difference problem1.jpg)

could anybody please tell me another way to achieve this structure, it doesn't matter if the shape of the pipe and the sphere change, as long as it's a hollow structure with a gap on one side.
The end result i tried to archive should look like this (final example.jpg) but with a hollow structure.

Thanks a lot for your help