Isn’t Grand Occidental the same hotel as Occidental, just referring to the gated off "royal" section? I’ve stayed there a few times in their top tier suites and thats the way it seemed anyway. Occidental is still listed along with Allegro on the Barcelo website. They may have changed the name of the gated off section to Royal instead of Grand from looking at the names on Google maps. Both sections could be booked from the same site last time I looked.
While we are on the subject, if you can stand to miss the excitement of the downtown area, I would highly recommend the grand or royal level at Occidental. It has a really nice private seafood restaurant not accessible to the rest of the guests and you also get as many reservations at the other restaurants as you want and room service and top shelf drinks included. Food isn’t as good as some of the best restaurants in town, but pretty darn enjoyable. Hard to beat the level of relaxation that comes with not having to plan anything or go anywhere other than the dive boat. I do still go in town a couple times to hit the must visit restaurants like Punta Sur.
The resort is cut into the jungle so it feels much smaller than it really is. Also has a big sandy beach great for family or non-diving spouses and they will bring beverages right to your chair. Many of the dive locations are literally 5-10 minutes away and the good dive ops will pick you up if you don’t want the large boats from prodive.