We were three families converging from four countries, 14 in all, and Eos Villa served as a brilliant base on Santorini. The space is large and comfortable and the pool flat-out this-is-ridiculous divine. Loaves of fresh bread in the morning. George is an excellent host; I would strongly suggest letting his associate Katharina help you book activities (we did a 5h morning cruise, and she booked a wine tasting at Argyos and dinner at Pyrgos , not to mention a few bis transfers, hugely helpful, and all turned out exceptionally well). I would write more but suggest instead that, if you’re headed to Santorini with a large group, stop reading and book now.
Once you’ve booked, do consider renting a car as taxi transport can be unpredictable on the island. You’re an 8-minute uphill (though not both ways) walk to Imerovigli; the Imerovigli-Oia trail is easily accessible and makes for a fantastic if brutal running trail even if taken partway.