Hi NightCabbage, also the way you could achieve this right now (if the operations actually don't make bad results...) would be to take your middle section there as its own individual solid slab, and select the top and bottom faces and run Shell on that.

That will build a hollowed out result like this:





And the ring that remains there is the material that you want to have removed, so paste back in the original shape (do a ctrl+c before doing the shell above), so you've got both the original and the shelled one at the same time like this:



You can then select the original one and do boolean difference and select the ring one as the piece to remove.

- Michael