Soak the beans overnight in cold water to cover. (Or, instead of the overnight soaking, cover beans with water and bring to a boil; boil 2 minutes, remove from heat, and allow to soak 1 hour.) Rinse and drain; put beans into a large kettle with a tight-fitting lid.
Add 6 cups cold water to the beans.
Cover and simmer gently for about 2 hours.
Meanwhile cook the tongue; simmer in water to cover until tender (about 2 hours), peel, then slice.
Pre-cook sausages in simmering water for about 30 minutes; cut each into 3 or 4 pieces.
Cut the ham into 1 -inch cubes and the bacon into 1/2 -inch cubes.
Add all the meats to the beans.
At the same time add the onion, garlic, bay leaf, parsley, and orange peel.
Continue to cook slowly, adding water as needed to keep the liquid just above the level of the beans, until the beans are tender (about 6 hours).
About 1/2 hour before the cooking is complete, add the peeled oranges, which have been cut into quarters.
The mixture should be thick; if not, thicken with cornstarch, diluted first with a little water to make a paste.
Add salt to taste; remove orange peel.