Below is from the document. FYI.
2.Camera Group Ownership
•Any camera application MUST request a camera group ownership using request_ownership() API before power control and release the ownership using release_ownership()API at application exit.
•Each Xavier can capture independently as primary if they capture on camera groups exclusive to each other.
•A camera group can ONLY have one primary and one secondary for dual Xavier capture.
•For all dual Xavier cases, Xavier A is ALWAYS the Primary and Xavier B is ALWAYS the secondary.