Complex sentence: Curaçao and Sint Maarten (whose national team is already a member of CONCACAF), while Bonaire, Saba, and Sint Eustatius have become directly part of the Netherlands as the Kingdom Islands.
Split into simpler sentences: Curaçao and Sint Maarten, whose national team is already a member of CONCACAF. For their part, Bonaire, Saba, and Sint Eustatius will become directly part of the Netherlands as the Kingdom Islands.