Apex PhysX Destruction, but without using fracture?

I would like to create an Apex destructable, but be able to define the individual meshes for the chunks.

For example: I have a mesh for a wooden wall, which is made up of 12 planks. I want the planks to be the chunks.

If I use the fracture tool in PhysX Lab, then it slices up the entire wall mesh, like it is made out of glass.

Does anyone have experience in this that could shed any light?

Thanks in advance.