Yeah, if you want families to be at the ceremony it won't work. But Beaches does them:
http://www.beaches.com/general/wedding.cfm
And they are the same chain as Sandals, I've stayed at both and both were awesome.
I used to do a travel business on the side and we did one where I think everyone went to a Beaches resort for the first week, and then the couple went to a separate Sandals resort on their own for another week or so so they could have their own private honeymoon as well.