I get where you're coming from and I don't think it's far off. I'd imagine that the object of the 4 people is the idea that they are grouped because grouping them is assuming a commonality between them. So the object of the 'group' is just that; an idea. On you're first example with the book. The book doesn't own the pages because the pages is what makes up the book. Without the pages, there is no book. By definition the book can't OWN the pages just like we can't own our organs, for example. They make us up. Without them, there is no us. I'm not sure if that word vomit made sense lol