1. Combine ham, veal, and pork with eggs, salt, pepper, nutmeg, dry mustard, and thyme in a large bowl. Add onion, green pepper, and parsley and toss to blend. Add bread crumbs and apple juice; mix thoroughly but lightly. Turn into a 9 x 5 x 3-inch loaf pan and flatten top.
2. Bakeat350°F 1 hour.
3. Meanwhile, prepare sauce for topping. Blend brown sugar, cornstarch, dry mustard, and allspice in a small saucepan. Add apricot nectar, lemon juice, and vinegar. Bring rapidly to boiling and cook about 2 minutes, stirring constantly. Reduce heat and simmer 10 minutes to allow flavors to blend.
4. Remove meat loaf from oven; pour off and reserve juices. Unmold loaf in a shallow baking pan. Spoon some of the reserved juices and then the sauce over loaf. Return to oven 30 minutes.
5. Place loaf on a warm platter and garnish as desired.