In a well greased casserole, blend 2 cans cream of mushroom soup and 1 soup can milk. Drain and stir in 1 (4 oz.) can mushrooms and 1 (2 oz.) jar diced pimiento. Add 1/2 cup chopped green pepper and 1/3 cup minced onion. Stir in 1 (6 or 7 oz.) package uncooked macaroni twists or shells, 2 cups diced cooked ham and 1/2 pound cubed pasteurized process cheese spread. Cover and refrigerate 6 to 8 hours or overnight. Bake, uncovered in preheated 325 degree oven for 1 1/2 hours.