Zombie Pigmen Behavior

My Friends I and are having a pretty big issue with the nether currently. One of us accidentily hit a Zombie pigmen and as they do they became angry. So we left hoping that when we went back days later they wouldn't be angry anymore. Turns out they still were and still are, even after dying to them. So I pose this solution: If a player attacks a zombie pigmen the pigmen becomes angry. This stays the same. But if the player or players leave the nether or die to the pigmen, the pigmen should reset and become calm and not aggro anymore and this goes for all pigmen in the nether. This is like a hard reset to all pigmen in the nether.