Combine real objects with real objects

Hi all,

I am developing an Unity App. In my project, I want to use the AR camera to track real objects in a virtual environment. 

Considering that meta does not allow access to the oculus camera, I decided to use an external camera as a cameraAR for Vuforia. Thanks to the external camera, I can use ImageTarget or ModelTarget. I am still left with one problem. When I develop in Unity the virtual environment, I have to tell where the oculus camera (OVRCameraRig) is located versus the cameraAR (Vuforia camera). I would like to have them start overlapping, and when I go into play mode, have the overlapping cameras start in an aligned way. However,  Oculus only activates when it is used so this is not possible. Do you have any suggestions? 

best regards