In a large stock pot, saute onion, celery, carrots, garlic, and parsley in butter until soft but not browned. Sprinkle in flour and cook, stirring for 2 minutes. Add broth slowly, stirring as you add. Add milk, potatoes, Worcestershire sauce, dry mustard, allspice, celery seed, thyme, seasoning salt, dry white wine, cayenne pepper, and chicken granules. Allow to simmer and thicken, stirring frequently, until potatoes are cooked through (about 25 minutes). During cooking, break up potatoes with the back of a spoon. Serve warm.