Can we use different passthrough layers for each eye?

I'm wondering if I can use two different passthrough layers for each eye.

For example, I want to set the opacity for right eye to 1 and for left eye to 0.5. 
What I tried was adding passthrough layers to right/left eye anchors under the OVRCameraRig object and changing the opacity outside of OVRCameraRig using a script. However, it seems not working.

If anybody know if we could do this and tell me how to do that, I would really appreciate it.

I haven't tried adding 2 OVRCameraRig and add passthrough layer for each one.

I'm not sure if I can do that and even if I can, I would like to avoid it because I feel like I don't take the advantage of OVRCameraRig. (If this is the only option, I will try it though)

I really appreciate your help. Thank you.