Is there a way to hide the Vive Controller in the SteamVR lobby?

I am wondering if there is a way to hide the Vive Controller models in the SteamVR lobby.

I am creating a VR overlay app. This means I have a unity3D project that can access the SteamVR and OpenVR APIs etc. Is there something I can do when this project starts auto-hiding my controller models?

So far I have tried using OpenVR.System.CaptureInputFocus()

and OpenVR.RenderModels.FreeRenderModel( RenderModel_t *pRenderModel )

without success.

Has anyone achieved this, check out any VR app that achieves this, or if possible?

Many thanks,

Liam