I think your group would love St Maarten/St Martin. Plenty of beautiful beaches, great night life, wonderful duty free shopping. Something for everyone of you.

You have the french side of the island St Martin and the dutch side St Maarten. It’s called the friendly island so I’m sure you will meet many single people.

I would not do an all-inclusive on this island. It is the gourmet capital of the Caribbean. Plenty of grocery stores to stock up on the liquor and snacks.

You also have a couple of islands just a ferry ride away. St Barths , Saba and Anguilla. St Martin is famous for it’s Orient beach. ******* bathing is allowed.

Here is a link to the Island

My other suggestion would be Punta Cana in the Dominican Republic. Loads of all-inclusive resorts.

here is a link

If you have any specific questions come back, I’m sure you will get many suggestions on where to go. The Caribbean is full of desirable islands. Good Luck)