two adjustment RRFPR will let you adjust the max fuel pressure under boost. But can't adjust when the fuel pressure start to raise, if that makes sense. Basically, it'll start raising FP as soon as the boost comes in but it'll stop and start bleeding at set PSI.
you can find a way to controll the signal line with bleeder like boost controller and may be make one yo do what you want. that's my guess.
Z31 setup $250 8)