How would I, like in the courier quest, move the NPC(s - in my case) every time it's been established that the player has left the cell?

That was kind of confusing. This is what I want:

I'm creating a kind of thug quest, but it's far simpler. It's just having 3 NPCs like thugs spawn in the same cell the character is in, at the center location marker (via Change Location quest + Global variable condition I set), with a force greet package for the player. So essentially, Thug1 will have a forcegreet package for the player (how big should the radius of the forcegreet be for the three values of trigger, wait, and forcegreet?), and the other 2 "Thugs" will have an escort or follow package so they follow Thug1 around. When you change location and the proper global variable is at the right value, they will spawn at the center location marker of the cell the player is in. Once the player leaves the cell, the thugs will be moved to the next center location of the next cell. To do this, would I just stop the quest so it restarts, or is there something else I should do? And should I just use an OnLocationChange event for the player alias to check when they've left, and then disable my aliases and stop the quest? If so, should I just put the OnLocationChange event on the player alias, and if it is at the first stage then set the stage to the failed stage, which stops the quest so it may be reset?

Thanks for any help you can offer.