Brown hamburger in skillet with onion, mushrooms, and Worcestershire sauce. Drain fat and add sour cream--let simmer. Cut French bread in half lengthwise and toast in oven under broiler. Butter French bread and scoop meat/sour cream mixture evenly onto French bread halves. Cut green pepper and tomato into thin slices and place on top of meat. Broil for 5 minutes to cook tomato and green ppepper. Take out of oven and sprinkle Mozzarella cheese and cheddar cheese alternately over the top of the sandwiches. Broil until cheese is melted.