We had a similar retreat setup earlier this year and spent quite a bit of time comparing group travel options. Eventually we decided to go with hamptons limousine
https://www.ewlimo.com/ for the entire group. They offered a sleek executive van that comfortably fit all of us, with leather seats, Wi-Fi, and bottled water included. Everything felt professional and high-end, which helped set the right tone for the offsite. Plus, coordinating with their team was simple — they were responsive and flexible with timing. The trip out to East Hampton went smoothly and on schedule. It was a great way to keep everyone comfortable and focused before the meetings even began.