Cook fresh green beans with carrot and red bell pepper strips in boiling water to cover until crisp-tender. Plunge into ice water to stop the cooking process; drain and set aside. Cook yellow squash in boiling water to cover until crisp-tender. Plunge into ice water to stop the cooking process, and drain. Cut squash into 1/2-inch-thick slices, and remove pulp from center of each slice with a round cutter or knife. Secure vegetables in bundles with squash rings, and place in a lightly greased 13- x 9-inch baking dish. Cover and chill 8 hours, if desired. Drizzle bean bundles with melted butter, and bake, covered, at 350° for 20 to 25 minutes or until thoroughly heated.