Put the ham hocks and oxtail pieces in medium pot, two-thirds full with water, and boil about 15 minutes. Drain and rinse the meat under running water. Return the oxtail and ham hocks to the pot and refill with water as before. Add the bell pepper, onion, and celery. Add salt and pepper to taste. Boil until all the meat is tender (2 hours or more). You may need to add more water to the meat before it is done, but don't add more than 1 to 3 additional cups, because you want the gravy to be rich. Serve with rice or potatoes, and be ready for some lip-lickin' grub.
NOTE: After draining and rinsing the meat, I would use beef broth or stock instead of the water in the second boiling.
ANOTHER NOTE: I like to brown the oxtails before cooking.