To make Bean Soup Mix: Combine yellow split peas, green split peas, butter beans, borlotti beans, kidney beans, cannellini beans, onion, stock cubes, cumin and garlic powder. Store in an airtight container until ready to use.
To make soup: Bring Bean Soup Mix and water to a rolling boil in a large pot. Cover, remove from heat and let sit one hour.
Return pot to heat, stir in carrots and celery. Stir in ham hocks, bring to a boil. Cover, reduce heat and simmer two hours, until beans are tender, skimming fat as necessary.
Remove ham hocks from soup. Remove meat from bone, chop and return to soup. Heat through and serve.