Sprinkle unflavored gelatine over water in small bowl; let stand 1 min.
Mix 1/4 cup sugar and cornstarch in medium saucepan. Gradually whisk in juice and unflavored gelatine until blended. Bring to boil on medium heat; cook 5 min., stirring constantly.
Remove from heat.
Add dry gelatin mixes; stir 2 min. until completely dissolved.
Pour into 9x5-inch loaf pan sprayed with cooking spray. Refrigerate 1 hour or until firm.
Unmold.
Cut into 24 pieces. Coat with remaining sugar just before serving.