Shadow maps mixed with dynamic shadows.

I recently posted a thread with a problem similar to this one. In that thread I discussed ambient occlusion but I realize my problem involves shadows as well. So I’m inserting a very crude example image to help me explain the issue. In the image the shadows outlined in blue represent shadows cast by static objects which would be baked into a shadow map. The red outline is for shadows that are cast by additional, moving objects brought into the scene. I would like a setup so that Blender does not calculate the already baked shadows, but can still cast additional shadows from moving objects onto to the same surfaces. In other words, add new shadows without recomputing the shadows that are already present. How is this done? Or is it a non issue as Blender already takes this into account when rendering?

look if this is what you want;)


untitled.blend (607 KB)