Hello,
The idea behind this system is complex, all combat NPCs will have a behavior tree which she will be responsible for defining the position of each NPC within a combat formation. With this we will have a quadrant around your group, this marking will serve as a warning of opportunity for mobs, example would be, you are playing in a certain formation having a TANK in the forefront, two DPS on the flanks next to the TANK, in the center you have a HEALER and at the bottom a DPSL in the rear. Let’s say you are playing in the rear with ranged weapons and you decide to go a little farther away from your group, here you got out of formation, out of quadrant and now enemies that have an AI see that your formation is broken, so, now their focus will be on going after the weakest spot in your group. Even if you distanced yourself, it doesn’t mean it was a bad thing, I want you to be as tactical as possible, so anything is possible, any formation, tactics and thinking is valid. The difference will be how the enemy reacts to your tactics and formations.
Is this idea possible?