collecting_producers_nearby would be populated with buildings that have collect_map_ware (and this will guarantee that such building will be here only once)
producers_nearby is populated based on outputs, and one building will be listed n-times where n is number of outputs
collecting_ producers_ nearby would be populated with buildings that have collect_map_ware (and this will guarantee that such building will be here only once)
producers_nearby is populated based on outputs, and one building will be listed n-times where n is number of outputs