Make lobster bisque by boiling live lobsters in water to cook them while making seafood stock for the soup. Add the lobster meat, heavy cream, cream sherry, onion, carrots and herbs to the stock, and simmer until it is done.
Boil water in a large stockpot and add 4 live lobsters, ensuring that they are completely covered with water. Once the water begins to boil again, reduce the heat. Simmer the lobsters for 20 minutes, then remove them from the pot. Reserve 10 cups of the water, and simmer on low heat. Meanwhile, remove the lobster meat from the tails and claws of the lobsters. Cut up the remaining portions of the lobsters, and place them in the stockpot with 1 cup of tomato paste. Simmer on low heat for 90 minutes before pouring the stock through a sieve placed over a pot to remove the lobster parts, which can be discarded.
Place 1 1/2 cups of chopped onion, 1 1/2 cup of chopped carrot and 1 1/2 cups of chopped celery in a saute pan with 4 cups of stock. Add 1 sprig of thyme, 3 sprigs of parsley and 1/2 teaspoon of saffron to the mixture, and heat on high for 30 minutes. Add 1/2 cup of tomato paste and 2 tablespoons of black pepper, and simmer on low for 30 more minutes.
Drain the contents of the saute pan through a sieve into the stockpot containing the remaining stock. Heat on medium heat, and whisk in 6 cups of heavy cream. Mix 1/4 cup of cornstarch with 1/4 cup of water. Reduce the heat to low and simmer for 20 minutes before adding the cornstarch mixture. Simmer for 20 more minutes, and serve in bowls containing the lobster meat.