Cheesehead

The main retailers are Foodstuffs which are basically split into 3 zones (Foodstuffs Auckland, Foodstuffs Wellington, Foodstuffs South Island) which operate as 3 separate companies and definitely have 3 separate buyers (buyers are called category managers over here), operating under 3 fascias and Progressives Enterprises (PEL) which is an Australian company and they operate in NZ with 5 different fascias. Foodstuffs is a little bit like a coop/franchise with all the stores being owner operated. PEL is a corporate.
I don't want to bore everyone else with all the reams of information I could provide so if you want any further details send me a PM.

Hope this helps.