Heat a large skillet over medium-high heat. Cook and stir Italian sausage, onion, and garlic in the hot skillet until sausage is browned and crumbly, 5 to 7 minutes; drain and discard grease. Add andouille sausage; cook and stir until browned, 3 to 5 minutes.
Heat olive oil in a stockpot over medium heat; cook and stir celery, zucchini, yellow squash, red bell pepper, yellow bell pepper, and orange bell pepper in the hot oil until slightly tender, 5 to 10 minutes.
Mix the sausage mixture, black beans, Great Northern beans, vegetable juice, and chicken stock into vegetable mixture. Bring to a boil, reduce heat, and simmer. Stir in tomato paste, oregano, basil, and garlic pepper; simmer until flavors blend, about 15 minutes.