Rotate some coordinates in relation to an object's rotation

Hi guys,

So I'm stuck with this one. I don't have a deep knowledge of quaternions or anything of the sort, maybe someone who does might be able to help me.

I'm trying to get a 3d radar working. So for this, I make dummy objects, that are possitioned in the balldummy, relative to how the real objects are position in relation to the player. So far, this code works. If I turn, The objects change respectiveley

     void ModifyPos()
     {
         if (radarObjects.Count > 0) {
             for (int i = 0; i < radarObjects.Count; i++) {
                 if (radarObjectsOriginals [i]) {
                     float distance = Vector3.Distance (this.transform.position, radarObjectsOriginals [i].transform.position);
                     float percentage = (radius - (radius - distance)) / radius;
                     if (externalDisplayRadar) {
                         radarObjects [i].SetActive (true);
                         float distanceToWorkWith = radarDummyBounds;
                         float relativeDistance = distanceToWorkWith *percentage;
                         Vector3 relativePos = ball.transform.position - radarObjectsOriginals [i].transform.position;
                         Quaternion rotation = Quaternion.LookRotation (relativePos);
                         Vector3 negDistance = new Vector3 (0.0f, 0.0f, -relativeDistance );
                         Vector3 position = rotation * negDistance + ballDummy.transform.position;
                         radarObjects [i].transform.position = position;
                     } 
                 }
             }
         }
     }

However, I want the objects to also change in relation to the radars rotation (additionally that of the player).

I tried adding

 rotation = ballDummy.transform.rotation * rotation;

after

                         Quaternion rotation = Quaternion.LookRotation (relativePos);
 

which makes the objects change in relation to the radars orientation, but they no longer change in relation to the player...

how can I reconcile this two behaviours? Any thoughts much appreciated.