Somewhere in the Garry's Mod Workshop on Steam, there's an addon called 'NPC Tools'. This mod pack contains several added tool gun functions that are specifically designed to manipulate NPC behavior.
One of my favorite NPC Manipulating mechanics within this addon is called 'NPC Relationships'. A simple tool that allows you to change NPC interactions between the player and other NPCs. By default, Combine Soldiers hate Citizens. But with this nifty tool, you can make it to where these two enemy factions function side by side without a hitch. Another thing you can do is change sides entirely, set all Combine forces ally to the player, and set anything Resistance enemy.
Source SDK games work on built in 'AI_Relationships'. Simple point entities that define how an NPC class reacts when faced with another. Beit Attack on sight, or Ignore.
Here's the point:
Minecraft has many different mobs with their own defined factions in place. Passive Mobs, Hostile Mobs, Neutral Mobs, Illagers, Villagers, etc. I was wondering if there was a type of Mob Relationships Mod that allowed you to customize mob interactions.
For instance: Zombies and Skeletons attack each other on sight; Villagers and Iron Golems hate the Player, while Illagers are friendly to the player; Iron Golems and Wolves attack Creepers instead of ignoring them; Wolves, Sheep, Skeletons live in harmony, and Cats and Creepers no longer repel each other.
If there's already a mod out there that does this, I would love to know about it.