Cut tops off the peppers, and remove ribs and seeds. Chop edible portions of tops; set aside. Bring a large pot of salted water to a boil. Add peppers, reduce heat, and simmer until tender but still firm, about 5 minutes. Drain and set aside.
Heat butter in a medium skillet. Saute reserved chopped pepper, onion and celery until tender, 3 to 5 minutes. Stir in crushed tomatoes, tomato sauce and garlic. Season with basil, oregano, 1 1/2 teaspoons salt and 1/4 teaspoon pepper. Simmer uncovered for 10 minutes. Preheat oven to 350°F.
Meanwhile, in a large mixing bowl, combine 1 teaspoon salt, 1/4 teaspoon pepper, Worcestershire sauce and Parmesan. Mix in hot sausage, mild sausage, bread crumbs and 1 cup of the tomato sauce mixture.
Using a piping bag or sausage stuffer, fill each pepper with the meat mixture. Please in a 3 quart casserole dish and pour remaining tomato sauce mixture over peppers.
Bake uncovered in preheated oven for 1 hour.
You can also place the stuffed peppers upright in a crockpot or slow cooker, cover with tomato sauce and cover; cook on high or low heat depending on the time available, until tomato mixture is boiling and meat is cooked through.