Oculus Integration: Making the controller vibrate when grabbed object collide?

I'm using Oculus integration to make items grabbable, in my case I want to make the controller, which is holding the object, vibrate when the held object collides with something.

For example, if I'm holding a pen with the right hand, i want to make the Right controller vibrate when the pen collides with the whiteboard.

How can I do it using the Oculus integration components?

In particular, the hard part is to detect which is the controller holding the object.