Clamping position of camera when using RotateAround?

Im making a game where the player rotates a camera(child of a camera holder) around a planet. I need to be able to clamp the position (and rotation) of the camera at certain points in time. Im using a RotateAround function and I was wondering if someone could help me to be able to clamp this? My code is below:

  private void RotateCamera(Vector3 dragStartPosition, Vector3 dragEndPosition)
     {
 
         //normalised for odd edges
         dragEndPosition = dragEndPosition.normalized *planetRadius;
         dragStartPosition = dragStartPosition.normalized * planetRadius;
 
         // Cross Product
         Vector3 cross = Vector3.Cross(dragEndPosition, dragStartPosition);
 
         // Angle for rotation
         float angle = Vector3.SignedAngle(dragEndPosition, dragStartPosition, cross);
 
         //Causes Rotation of angle around the vector from Cross product
         holderTransform.RotateAround(planet.transform.position , cross, angle);
 
         EventHandler.instance.AddHiddenEvent(EventHandler.EventType.panCamera);
     }
 
 
     private static Vector3? GetMouseHit()
     {
         RaycastHit hit;
         int layer_mask = LayerMask.GetMask("Planet"); //raycasting on the planet
         if (Physics.Raycast(Camera.main.ScreenPointToRay(Input.mousePosition), out hit, Mathf.Infinity, layer_mask))
         {
             return hit.point;
         }
         return null;
     }