Roy's Waikiki. Roy's has a website but not for this particular restaurant, so I'm not sure if they have a private area, but all it takes is a phone call. I was there several months ago. We had a party of about 20 in a semi-private area. For folks who have never been to Hawaii, this is a perfect restaurant. It's walkable from your hotel, has steak and seafood options, beautiful surroundings.