In LeSS, unlike other scaled approaches, there is only one Product Owner. This is a key characteristic of the framework and it is intentional with the purpose of supporting whole-product focus and thinking. In addition to having a single PO, less enables whole product thinking through outlining the following 3 guidelines:
Parts of software that are not integrated into the whole product have no value yet.
Teams who finished ‘their part’ are not done until it is integrated.
Whenever there is a choice to optimize a team output or the whole product, we always chose the whole product.