This isn't possible without shaders and some custom handling of how far the light can go inside the object.
I saw a tutorial about replicating Terraria's light system once. But it is not easy. And it would need to be handled differently for other shapes.
#2d lighting physics issues
night sparrow
A more straight forward solution would be to make the occluders smaller than the wall, so they prevent the light from going past it, but at least allow some part of the wall to be illuminated