F150 Dual Tank 5.8L Fuel Rail Crossover Rear Lines (crumbling)

Hello: I'm new to the forum and not a mechanic. I'm mostly a junkyard replacement parts guy, which has worked in most instances over the years (79+). I recently detected leakage in my tank(s) fuel supply lines and replaced those. However, after connecting the lines to the Fuel Injector Rails at the Regulator on the Driver's side, I discovered the Crossover Rubber (or Plastic) lines had deteriorated and were crumbling. Unfortunately, I can not see under the Plenum to determine where they connect on the passenger side. Does anyone have experience with these two lines and know if they can be replaced without removing and buying the entire Rail system. Also, if they can be replaced separately, does anyone have a part number or nomenclature.