No, I think you're right. If they are all bunched together, they are probably all taking damage. But it's not supposed to be that way :)
Haha, it could be an unintentional mechanic - it made me think of a different strategy, so it wasn't a bad thing! But I get it if that is not your intention / hope for the game. Still a fun one nonetheless! I had fun trying to beat all the levels!
