This is just one example:
Why should we worry about the hormone level in our body or bodies?
In postmortem, doctors found that they all (dead) had poison in their stomach or stomaches?
Okay, is there any example sentence that uses "...plural....and singular something that belong to that plural?" as in my first options of 'body' and 'stomach'?
Frankly, I don't find any problem in using body over bodies there. It's understandable.