Process:
- Create points for the the stores and warehouses based on Lat and Lon
- Append data to match each store with each warehouse
- Calculate distance from each store to each warehouse
- Sort by Store and by Distance (ascending) from store to warehouse
- Select every third record (since there are 3 warehouses, given the sort from above, this will give the warehouse closest to each store
- Join results with list of items to be shipped to each store
- Calculate miles for every item (Distance * number of items)
- Group by item, sum miles per item