1. In a saucepan, mix the jello powder with the pineapple and the pineapple juice from the can the juice, add the drained oranges.Heat over medium high heat. When it just comes to a boil remove from the heat and allow to cool 30 minutes.
2. In a large bowl, mix the jello mixture with the buttermilk until well incorporated. Fold in the cool whip and pecans. Pour into a jello mold or just a regular glass or tupperware bowl. Chill at least 2 hours or overnight.
3. When ready to serve, unmold onto a plate, or just scoop from the bowl.