Dual Shock 2 does not use wires, but plastic ribbon cable that is pretty much impossible to hack. But if you were to hack say the PSOne Dual Shock , you could get access to the wires for R1, but since the Triangle is a button is just two contacts on the main PCB (no wires) most you could do is wire up R1 to also function as Triangle (no way to change triangle to anything else). Sorry.