Using a food processor, pulse the cranberries, orange, pear and 7 tbsp. sugar until the fruit is coarsely chopped.
In a medium saucepan, combine 1 cup cranberry juice, the gelatin and the remaining sugar. Let stand for 5 minutes to soften the gelatin. Bring to a simmer over medium heat, whisking until the gelatin is completely dissolved. Stir in the fruit mixture and the remaining 12/3 cups cranberry juice. Transfer to a 5-by-9-inch nonstick loaf pan. Refrigerate for at least 6 hours or overnight.
Run a warm thin knife between the outer edge of the gelatin and the pan. If needed, fill a large baking dish with hot water and dip the pan in the water to help loosen. Carefully unmold the cranberry sauce onto a serving platter.