Domaine Chandon has a very good restaurant (or at least they used to be a decade ago when I went there). It’s an actual restaurant, though - not sure if you wanted it to be a dinner in a winery that wasn’t actually in a restaurant of theirs.
Screaming Eagle will let you have a dinner party there, but you have to arrive by helicopter.
Etoile (the Dom Chandon restaurant) closed doors end of 2014. Legacy loss in the valley…
That said, I imagine the space is now more conducive to private gatherings but dont have any information on such
Joseph Phelps if they can is an excellent choice. We’ve had a remarkably wonderful times there with excellent food. And their wine speaks for itself. However talking about lunch. Gall has facilities as well, a truly amazing cave dining room. Flora Springs may be able to accommodate you. First choice for me is Phelps, their gracious hospitality has earned my loyalty. Longshot for something different is the Caves of Soda Canyon.