In my attempts to create a hollow object, I have tried separating the faces into unique objects, but that requires each to have an acceptable thickness, and though using solidify you can get a decent result for a single plane, when applied to other planes, the voxels don't align. Currently the only thing I can think of is having each face be a unique .nbt, but that sounds terrible and painful. I'm still learning Blender, so if you have a method I'm eager to hear it, otherwise this is my suggestion.