Place chickens in large, heavy pot. Add 2 quarts water, onions, chopped celery, carrots, parsley, salt and white pepper and bring to boil. Skim off any scum that rises to top. Cover, reduce heat and simmer 1 1/2 to 2 hours or until chickens are very tender. Remove chickens from pot and set aside. Strain broth. There should be about 7 cups. Return broth to pot and add soy sauce, sherry, ginger juice and sesame oil. Strip chicken from bones and dice. Add to broth and bring once more to boil. Place in chafing dish over heating unit and keep it at simmer.
Arrange tofu, noodles, green onions, mushrooms, water chestnuts, julienned celery, red peppers and cilantro leaves in bowls around chafing dish. Ladle broth into bowls and let guests add ingredients of their choice. (Keep broth very hot, as addition of extra ingredients will cool it.)