How to get two Google Cardboard Camera Rigs

Using Unity, I want to have two camera rigs that a player can swap between, but when I use two of the Google Cardboard prefabs, I get an error saying there can only be one google cardboard in a scene. It still works in the Editor window (despite the error), but when I build to android it doesn't. I know with Oculus you can get around this by separating out the OVR Manager script-- does anyone know if there's something similar for Cardboard? Thanks!