Place parboiled rice in a large bowl and cover with warm water. Set aside. Wash heads of garlic. Set aside.
Heat sunflower oil and margarine in a cauldron over high heat, then add pork, turning occasionally until the pork is evenly browned, about 10 minutes. Stir in the onions; cook and stir until the onion has softened. Stir in the carrots; cook and stir until the carrots have softened. Sprinkle with cumin and pepper. Drop whole garlic heads into the mixture, stirring to evenly distribute ingredients. Reduce heat to medium. Cover and cook for 20 minutes.
Wash and drain parboiled rice with hot water. Pour cleaned rice over the pork mixture in an even layer. Slowly pour in boiling salted water. The rice should be covered with about 3/4 inch of water. Do not stir. Reduce heat to medium-low. Cover and cook until rice is tender, and the liquid has been absorbed, about 20 minutes. Stir rice and pork together, and serve with the garlic heads on top.