Possibility to map on destination object for Deep array object mapping

[furang]

The problem:
I have Order and Product entities in doctrine (One Order has Many Products). I receive Order object from api (not Order entity) with Products inside (also not doctrine entity). And i want to update data in db.
For Order I can check it in DB, get and map changes on existing Order entity (I can pass existing entity as $destination).

...
$order = $this->orderRepository->findOneBy([
    ...
]);

if (null === $order) {
    $order = new Order();
}
$this->mapper->map($orderData, $order);
...

But for products all I can do is just

....
->filter('products', new ArrayObjectMappingFilter(Product::class))
....

And this creates new unmanaged entities. And I want to map data to existing products. Is it possible? Or mb you can give me a hint how it can be implemented.