Re: one true listing
>Does anyone know if there are guidelines for editors to follow regarding subsidiary organizations, or is each editor's opinion the determinant of what's 'separate enough'?
No, that would be editor's judgment. Examples like Ford Aerospace/Tractors/Lotus/Mazda, etc., are very obvious. So are cases like the jerk who boasted he (personally) had forty-nine online businesses (and wanted them all listed.)
We'd consider size, organizational independence, personnel and locational independence, taxonomic independence, and other factors.
For a small local business that offered cosmetic products and services onsite, and mail-order cosmetic products, ... that looks like one website to me. That one website might be considered for listing in Shopping and Regional both...if it were spread over two different domains, the editor's spam-sensors should be flashing, and they should look VERY carefully before giving two listings.