Boil oysters until firm; drain, but save water.  If oysters are fresh, save water from oysters, too.  May need to put water through a strainer until comes out clear.  Separately boil gizzards until tender; drain and set aside.  Brown beef in skillet until thoroughly cooked.  Once oysters and chicken livers are cooled, add them and chicken liver to food processor and chop until mixture resembles a paste.  Set aside.  Once beef is browned, drain, then add onions and cook 15 minutes.  Add bell pepper, parsley, garlic and celery and cook 15-20 minutes, stirring continuously.  Add oyster mixture to ground beef mixture.  Stir together and add beef stock and water reserved from oysters.  Bring to a boil.  Lower fire and simmer 1 1/2 to 2 hours, stirring frequently to prevent sticking.  Add salt and pepper to taste; cook 10 minutes.  Add cooked rice a little at a time until you reach desired consistency (not too sticky nor too dry).