Launching to external application.

Hello, 
I'm currently working in Unity to create a VR hub application that links to three VR experiences that reside in their own separate executables.  Currently, I drop out into the OVR white room when transitioning from one executable to another.  On SteamVR, I'm able to mask this transition by using their Load_Level script to launch the external process while fading into a customized compositor scene during the transition.  I noticed that OVR_Overlay allows me to customize the white room by loading in a cubemap.  Is there a way to get this customized overlay to persist as I switch executables?