Strain the juice through a double layer of damp cheesecloth or a paper coffee filter. Measure 3 cups of the juice. Sprinkle gelatin over to soften.
Meanwhile, bring the remaining 3 cups of juice to a boil in a small saucepan. Add the sugar, stirring to dissolve. Remove from heat as soon as it dissolves, and stir in the juice and gelatin mixture. Pour into a glass bowl, and allow to cool. Cover with plastic wrap, and refrigerate overnight. Garnish with zest and pomegranate seeds.