How can I make the AI in my game wait in lines?

Hello I am making a 2.5D isometric restaurant management game where the player controls the inner working of their own restaurant. What I am having trouble doing and finding information about is making the customers of my game wait in lines and stop behind each other when there is already somebody occupying the way point or space in front of them.

Because it is supposed to be a restaurant the AI needs to wait in line just like in real life.

I'm not sure if it will help but here is a copy of my script that allows the customers to seek out way points and act in a semi-believable way. I use a nav mesh for the detection of objects.

var waypoints : Transform[]; var waypoint : Transform; var currentWaypoint : int; var agent : NavMeshAgent;

function Awake(){ agent = gameObject.GetComponent.(); agent.speed = Random.Range(2.5, 5); }

function Update () { waypoint = waypoints[currentWaypoint]; agent.SetDestination(waypoint.position); }

function OnTriggerExit(other : Collider){ if (other.name == "0 Start"){ currentWaypoint = Random.Range(1, 3); } }

function OnTriggerEnter (other : Collider) { EatMeal(); if (other.name == "0 Start" || other.name == "3"){ currentWaypoint++; } if (other.name == "1"){ WaitForSoda(); Debug.Log("Is Waiting"); } if (other.name == "2"){ WaitForFood(); Debug.Log("Is Waiting"); } if (other.name == "4 End"){ Destroy(gameObject); } }

function WaitForSoda(){ yield WaitForSeconds(2); currentWaypoint++; }

function WaitForFood(){ yield WaitForSeconds(5); currentWaypoint = Random.Range(5, 12); }

function EatMeal(){ if (currentWaypoint >= 4 && currentWaypoint <= 12){ yield WaitForSeconds(Random.Range(5, 12)); currentWaypoint = 3; } }