Texture baking order

Hey guys, quick question. Is there a way to control the process of baking order-wise?
I had a situation similar to the one in the attachment picture, basically I want to save some space but overlapping one island over another, provided that “bottom” one has some unused (black) space on it. Now, is there a way to force blender to bake circle island as the last one so it overlays the cube UV’s? I know I can just separate objects in this particular case, than bake them separately, but in my current project it would be way convenient if I could just fix the baking process and work within one object.