Cook mostaccioli until al dente in boiling salted water. Drain and set aside. In skillet, combine meat, sausages, onion, green pepper and garlic. Cook breaking up meat, until meat is browned. Drain off fat. To the meat, add all remaining ingredients, except egg and cheeses. Bring meat sauce to a boil. Reduce heat. Cover and simmer 15 to 20 minutes, stirring occasionally.
Meanwhile, combine egg and cheeses. To assemble, stir cooked pasta into meat sauce. Place half in 1 quart buttered baking dish. Spread cheese mixture evenly over the top. cover with remaining pasta. Bake, covered, at 350 for 30 to 35 minutes or until cooked through. Serves 4.