Multiple Sites, Identities

We are a new NS customer just beginning our implementation and are running into challenges.  We are trying to grapple with the issue of selling the same inventory from our warehouse across different storefronts (brands) so that pricing for an item can vary across these different storefronts and the customer can have a branded Customer Center.  

Any tips for tracking orders by storefront as well as how to maintain separate web identities for our multiple storefronts, some of which will be hosted by NS while some of which will be tied into NS as System of Record through WSDK or other data communication.  Ideally, there would be a designator on each transaction to identify the storefront for that transaction.  Also, we'd like to track business by each storefront, so that we could see that Storefront A did so much in sales, Storefront B, etc.