Bring 6 cups of water, 1/4 cup margarine, and 3 cups of rice to a boil and simmer until cooked. Keep cooked rice in the large pot.
While rice is cooking, brown the ground beef with 3/4 of your onion chopped.
When ground beef and onions are cooked, mix in with white rice and set aside.
Mix 1-1/4 cup of tomato juice with 1/2 cup water and set aside.
Melt 1/2 cup margarine (or butter) with remaining 1/4 onion chopped.
Lay aluminum foil on the bottom of a large casserole dish and spoon one layer of tomato juice and remaining 1/4 onion mixture.
Take a cabbage leaf (roughly the size of your hand) and lay it flat. Take a small spoonful of your rice and beef mixture and place it on the top 1/3 of the cabbage leaf. Begin to fold the edges over the rice/beef mixture. Shape and roll the cabbage leaf and rice/beef mixture to the bottom.Tuck in both edges of the cabbage roll.
Place cabbage roll in your casserole dish. Continue to layer cabbage rolls into two layers in your casserole dish. In between the first and second layer, and on top of the second layer, add more tomato juice mixture along with onion.
Pour melted butter and onions over the two layers of cabbage rolls in the casserole dish.
Cover second layer with a few remaining cabbage leaves and place foil over top.
Bake in a 325 F oven on the middle rack for approximately 2-1/2 - 3 hours or until cabbage is soft.