For a smooth drink, make a simple syrup by mixing 2 cups water with 1 1/2 cups granulated sugar in a saucepan. Bring to a boil and stir until sugar is dissolved. Cool before mixing with the juices by adding more of the water planned for the container.
Squeeze the juices from 4 each of the lemons, limes and oranges; pour into a gallon container.
Thinly slice the remaining fruit and set aside for garnish.
Add water and simple syrup to the juices; mix well. Store in the refrigerator. Serve over ice with fruit slices.