There are two extremes. Obviously General Electric (which makes light switches, power plants, and nuclear submarines) has different divisions. Equally obviously, the gonif who boasted in another forum that he had fifty-seven businesses (by which he meant, fifty-seven websites taking orders for fifty-seven different product lines, none of which he supplied, sold, or supported) doesn't even have one. Obviously, you aren't _really_ close to either. Well, all three collectivities have ONE CEO, so we would be looking at other things to make the distinction.
I think the clincher for us is when you say "the people who are looking for xxx are not the same as the people who're looking for yyy". That tells us the distinction is for marketing purposes, which is pretty well determinative for us: we won't recognize it.
You don't see the chairman of GE explaining to his board, "you see, we really need separate websites because, um, we sell coal-fired power generators to the department of defense, and nuclear-powered fast attack subs to the city of Cleveland ... or something like that." You don't see Walmart setting up separate divisions because the people who buy fishing tackle are not the same people who by fabric by the yard.
You can set up however many websites you want. But the one we want to list is the one that points to all the neat things the company does (whether on one domain name or a dozen.)