There isn't a formally organized, centralized "Waldorf Astoria Alumni Association." The Waldorf Astoria brand is a luxury hotel brand owned by Hilton. Unlike universities or other institutions with structured alumni programs, there's no network specifically for people who've *worked* at Waldorf Astoria hotels, nor for guests who have *stayed* there.
While individual Waldorf Astoria hotels might have their own internal networks for employees, there's no overarching alumni organization connecting people across the entire brand.