Very-Berry Rhubarb Jam

In a 4- to 6-quart heavy pot, combine rhubarb, sugar, and the water. Bring to boiling; reduce heat. Simmer, uncovered, for 5 minutes, stirring constantly.

Stir in blueberry pie filling. Return to boiling; boil for 6 minutes, stirring constantly. Stir in gelatin. Return to boiling; boil for 3 minutes, stirring constantly.

Ladle hot jam into half-pint freezer containers, leaving a 1/2-inch headspace. Seal and label. Let stand at room temperature for about 8 hours or until jam is set. Store for up to 3 weeks in the refrigerator or for up to 1 year in the freezer.