I solved my problem. See below code.
Now two Canvas3D receive a same mouseRotate behaviour.
Let me know if there is more better and efficient way.

Sungwoo

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public class MouseSync implements MouseBehaviorCallback {

   public MouseSync() {

       ......

   }
             
   public void threeDSceneCreation() {

       ......

       MouseRotate myMouseRotate = new MouseRotate();
       // Mouse rotate event capture to synchronise the axis view rotation.
       myMouseRotate.setupCallback(this);
       this.transformChanged(MouseBehaviorCallback.ROTATE, matrix1);
    myMouseRotate.setTransformGroup(tg1);
    myMouseRotate.setSchedulingBounds(new BoundingSphere());
    childBG1.addChild(myMouseRotate);

    MouseTranslate myMouseTranslate = new MouseTranslate();
    myMouseTranslate.setTransformGroup(tg1);
    myMouseTranslate.setSchedulingBounds(new BoundingSphere());
    childBG1.addChild(myMouseTranslate);

       MouseZoom myMouseZoom = new MouseZoom();
       myMouseZoom.setTransformGroup(tg1);
       myMouseZoom.setSchedulingBounds(new BoundingSphere());
       childBG1.addChild(myMouseZoom);    
       
       rootBranchGroup.addChild(childBG1);
   }
   
   public void transformChanged(int param, Transform3D transform3D) {
       //------------------------------------------------
       // For all behaviour sync i.e., rotation, zoom, translation.
       //------------------------------------------------
       // axDis.tg.setTransform(transform3D);
       
       //------------------------------------------------
       // For roation behaviour sync only.
       //------------------------------------------------
       Quat4d q4d = new Quat4d();
       AxisAngle4d a4d = new AxisAngle4d();
       // Places the quaternion equivalent of the normalized rotational
       // component of this transform into the quaternion parameter.
       transform3D.get(q4d);
       // Sets the value of this axis-angle to the rotational equivalent  of
       // the passed quaternion.        
       a4d.set(q4d);
       // Sets the rotation from a transform3D data.
       transform3D.set(q4d);
       transform3D.setRotation(a4d);
       // Set the new rotation info to the target Canvas3D.
       axDis.tg.setTransform(transform3D);
   }    
   
}