Sorry I thought I remembered you posting about little ones.... got my user names mixed up.  🙂 I'm told you can make your reservations for the Beach Club onboard the ship.... with the suite/diamond concierge or through the head waiter in the dining room.    My wife said the head waiter asked us about reservations for the beach club on the first night... but I was too busy coming down off the luggage fiasco to pay attention.   So Nachi ---  kidless and with a group you'll be fine.