Blend together the 4 tomatoes, 1/2 onion and 3 cloves garlic to make a fine liquid. Heat oil in a medium saucepan over medium heat and strain the tomato liquid in through a colander. Simmer a few minutes until it changes colour, then add the 10 cups chicken stock and bring to a boil.
Meanwhile, in a mixing bowl combine the mince, 3 diced tomatoes, diced onion, mint, oregano, egg, rice, salt and pepper. Mix well and use your hands to form golf ball-sized meatballs.
Using a ladle, gently lower the meatballs into the simmering soup. Let simmer until the meatballs float, then add the zucchini, carrots and chokoes. Taste for seasoning, then cover and cook on low until vegetables are tender.