How to create double walls and doors from an organic SubD model?

Hello I’m new to Rhino and Grasshopper and I’m still learning SubD workflows.I have an organic building model made with SubD, and I want to divide it into architectural elements, mainly:double walls (wall thickness),doors and openings,walls that are not 100% geometric or planar (organic / curved walls).

What I’m trying to achieve:Take one organic SubD volumeSplit or subdivide it into walls, doors, and spacesKeep everything editable in SubD if possible (not converting too early to NURBS or meshes)