PDF layers parent and child visibility problem

Can anyone tell me how to make parent group linked to child group.

Let me explain my problem with simple example.

I have two group layers(OCG) OC1 and OC2. OC1 is the parent and OC2 is the child inside OC1.

OC2 turns on and off the layer properly.
OC1 does not have control on (OC2)layer visibility.

How do I set that?