Well, I dound the bloodhowlers were linked-not in the extreme and annoying way of EQ2, but still linked-Ihaven't split with my monk, but I know my Pally would pacify one of the 2 that walk together and I would pull the other, the one I pulled would run towards me (off its usual patrolling path) and the other, though lulled would follow, not running, walking calmly and keep following his partner until the lull eventually wore off and then he attacked

Have you tried to split them with nerve strike ?

Lets say 3 mobs are supposedly linked. You pull the 3 to you, FD, nerve strike one, re FD and let the 2 go back.
If you wait the full 30 secs, they should be far enought and the nerve striked mob should still be on you. If you get aggro from the other 2 once you get up, then it means they are linked. If not, they are splitable.
I dont have lull, but when you nerve strike a mob part of a patrol and FD, the other mobs keep patroling, and the one you nerve striked is "rooted" : it doesnt move, but tries to follow his "patrol mates" walking without moving.
I suppose that lull doesnt break the "patrol script" or something.

By the way, so far every type of mob i've tried to nerve strike was affected, and i never got any resists.
Am i lucky ? or nerve strike is not resistable ? and are there mobs immune to nerve strike ?

Aye thats the spot, Sleeping moon.  You may find that when you nerve strike and FD, the other two instead of going back will just linger around their buddy until the guy is no longer stunned.  Certainly lulling doesn't break the link, it will be interesting to see if FD does

While they path together they can be split  same with the roamers in APW.The way this works is there is always a leader and a follower or followers.To break the link nerve strike a follower ,The leader will continue  with whatever other followers  if any are with him..make sure you give lots of room because these roamers have overly large assist range on each other.

It is easy to see who is the leader and who is the follower..simply pull the mobs back a bit then fd..the leader will always run back to origin of pull while followers will always walk back slowly.Using this knowledge you can also solo split these types of mobs using seperation from their leader because he runs and they walk giving you he seperation easily.Again you need lots of room because they reassist at abnormally large range,but they can be fd split .

I've FD split the bloodhowlers patrols with no problem at all.
I'll check Kivik's affirmation regarding leader/follower "scripting".
Kivik, since you're pulling in APW, can you tell us if some mobs are immune or can resist it ?