https://valorantesports.com/en-US/news/game-changers-2024-championship-expansion--new-mobility-policies
They outline the concurrent ownership exception in this article.
Exact quote: "An organization already fielding a roster in the Challengers Leagues will be allowed to field a second team that competes in Premier or a Challengers League, provided 3/5 of the roster are Game Changers eligible."