Hi, I have not tried this but I think this is possible.
You can just consider only one body Id and not all the body id's..
for (auto& body : bodies)
printf("Processing frame #%d body %d left hand: %u\n",
bodyFrame.frame_index(), body.id(), unsigned(body.hand_poses().left_hand()));
// Pixels in the body mask with the same value as bodyId are
// from the same body.
const auto& bodyId = body.id();
if body ID is '0' ---> you do something.
Rest body Id's are neglected automatically.