Trim all fat from beef.
Place steak in a heavy kettle or Dutch oven.
Add water, beef broth, onion and garlic.
Place parsley, bay leaf, peppercorns and thyme on a small piece of cheesecloth; bring up corners to enclose herbs; tie securely; add to kettle.
Heat to boiling; lower heat; cover.
Simmer 1 hour.
Add chicken breast; simmer 30 minutes, or until meats are tender.
Remove meats; keep warm.
While meats cook, pare carrots and cut in sticks; trim zucchini, cut in sticks.
Reheat broth in kettle to boiling; add carrots; cover.
Cook 15 minutes.
Add zucchini and celery sticks; cook 15 minutes longer, or until tender.
Remove.
Strain broth into a large bowl, pressing onion and garlic through sieve into liquid; let stand about a minute, or until fat rises to top, then skim off.
Carve meats; combine with broth and vegetables in a heated tureen.