Product photography: group shots editing

Product photography: group shots editing.
Why group shots require different type of editing? In attached picture I needed to extract each product, create a new layer and do individual editing to it: in black object you have to show details in shadows. In white one you need to show the panel with all details and stretch it in different directions to obtain 90 degrees perfect rectangular shape. Colour adjustment is important. All three objects need to be re-positioned and leveled. If you have any questions while shooting products please .