ChromatiCraft has a (late-game) cloaking tower that disables mob-to-player targeting in its range. One of the things I had in mind when writing it, but apparently does not work, is for the long-range sight capabilities in Zombie Awareness to also be nullified if the would-be target is in that range.

The simplest way to implement this is probably a custom Forge event, ZombiePathFindEvent, which has data on the target location (world,x,y,z), the EntityZombie (or derivative thereof), and what type of detection (light, blood, etc), and then, if the event is cancelled, not pathfind.