Ensuring a group of navmesh agents stay put.

Hi, so I want a group of navmesh agents to move toward a target location and within a few units to STOP. The group is controlled in formation by a leader, which has the below script attached to it. If the target moves away, I want them to follow.

Right now I have them moving to the target location, getting there and swarming all around to try and reach the target location, despite my efforts to prevent this.

Here is my code:

 void Update()
     { 
         //Need to see if units are being destroyed.
         groupStrength = group.Count;
         //If distance between you and the nearest enemy is less than detection radius. 
         var thisRoutine = StartCoroutine(Track());
 
         if (CheckDistance() <= combatRadius)
         {
             StopCoroutine(thisRoutine);
             leaderAgent.Stop();
 
             Engage();
 
         } else if (CheckDistance() <= combatRadius) { StartCoroutine(Track()); }
        
     }
 
 
     public IEnumerator Track()
     {
         //We want delay, so that the enemy formation is circumventable. 
         trackerTimer -= Time.deltaTime;
         if (trackerTimer <= 0.0f)
         {
             if (CheckDistance() <= detectionRadius)
             {
 
                 target.transform.position = nearestPlayerUnit.transform.position;
                 Debug.Log("Position acquired");
 
 
                 yield return new WaitForSeconds(0.0f);
             }
             trackerTimer = 2.0f;
         }
     }
 
 
     private float CheckDistance()
     {
         float minDist = Mathf.Infinity;
 
         foreach (GameObject playerUnit in playerUnits)
         {
             distance = Vector3.Distance(transform.position, playerUnit.transform.position);
             if (distance < minDist)
             {
                 nearestPlayerUnit = playerUnit;
                 minDist = distance; 
 
                 //We don't need to get the leader because that will be done in the inspector.
 
             }
 
         }
        
         return distance;
 
     }