I'm not so sure. I'm no expert, but cichlid's from different geni are bred together to form the blood parrot and the flowerhorn. All Ps are characins and therefore similiar genetically.
Piranhas don't do well with other species of piranhas, but you could hand vent the fish, fertilize the eggs, and then hatch the eggs in a separate tank. It might work. I'd have to know more about piranha genetics to say for sure but it might work....
