Pour 1 cup cranberry juice in a small bowl and sprinkle the gelatin over it . Let stand until gelatin softens, about 15 minutes
Combine cranberry, Splenda and 1 cup cranberry juice in a blender. Process until the cranberries are almost pulverized.
In a large saucepan, combine blended mixture with remaining 1 1/2 cup cranberry juice and lemon juice. Bring to a boil over medium heat, stirring frequently. Reduce heat and simmer, partially covered and stirring frequently, until cranberry bits are tender, about 8 minutes.
Remove from heat and stir in gelatin mixture until gelatin dissolves. Cool slightly and refrigerate until firm, at least 8 hours.
Keeps under refrigeration for 2 to 3 days.
NOTE: STRAIN HALF THE BATCH TO MAKE A SEEDLESS OPTION FOR THOSE WHO WANT SMOOTHER SAUCE