In small bowl, combine mayonnaise and garlic. Preheat oven to 500°F

Heat oil in large skillet over medium heat. Suate beef until slightly browned. Stir in green peppers and onions. Add salt and pepper. Saute until vegetables are tender.

Spread mayonnaise on buns. Top with cheese and sprinkle oregano.

Heat sandwiches in oven until cheese is melted or slightly browned.