Oculus OVR Grabber script. Can I use the Index Trigger instead of the hand Trigger?

I have created a VR scene in Unity for use with the Oculus Rift. I have the OVR Grabber script attached to the hand objects so the user can grab objects, but the script will only let me use the "PrimaryHandTrigger". I think the "PrimaryIndexTrigger" would be more intuitive. I do not see any way to get the OVR Grabber script to use it. Does anyone know a way to get this script to use the Index Trigger instead of the Hand Trigger?