Substitute 1 small pink grapefruit for the oranges.
How to Section Citrus Fruit
Use a sharp paring knife to section fresh oranges or grapefruit. Cut a 1/2-inch-thick slice off both the top and bottom ends of the fruit. Cut the peel and white pith away from the fruit, using a downward cutting motion following the shape of the fruit. Place the peeled fruit piece on its side, then cut down along the membrane on both sides of each section to remove the fruit.