In a large kettle, cook rhubarb and water over medium-high heat for 3-5 minutes or until rhubarb is tender. Add sugar. Bring to a boil; boil for 2 minutes. Stir in pie filling, blueberries and lemon juice. Return to a boil. Reduce heat; cook and stir for 10 minutes. Remove from heat; stir in gelatin until dissolved. Cool slightly. Pour into refrigerator containers. Cool to room temperature. Cover and refrigerate.