Fixing Pigmen's Anger Issues

The Zombie Pigman mob is interesting in that it will call for backup from other Pigmen up to 40 blocks away. However, this has caused me (on several occasions) to land myself in a position where no matter where I go, Pigmen will always be angry, because already aggravated Pigmen will chase me (even when I hide in completely enclosed tunnels that they can't get to), and as they chase me, they will continue to "pick up" other Pigmen along the way. I think it would be wise to keep the horde mechanic, but only have Pigmen call for help when they are attacked, not just whenever they're angry. Also, exiting the Nether should calm down the Pigmen, because as of now, angry Pigmen don't forget about you when their chunks are unloaded.