This feature is a part of Smart Multiple Catalogs. Click here to see all Smart Multiple Catalogs features.
Each product catalog has a separate menu in WordPress admin. That means it is a completely separate product catalog with separate settings and categories.
Lets say that we have created 2 additional catalogs: Flowers and T-Shirts. The product related part of WordPress menu we look as follows:
If we want to add new flower to the Flowers catalog than we click Add New Product under the Flowers catalog menu or on the Flowers admin listing page.