I would imagine that getting a "fractional" started after-the-fact is a heck of a lot more complicated than starting out in a "fractional" in the first place.
(1) You sound "emotionally attached" to this house. So first you'd have to come to grips with, the fact that "your beach home" will no longer be "your beach home."
(2) You'd better get yourself a decent lawyer to draw up the contract and ensure that it addresses each and every contingency from how cleaning & service contracts are administered; to who secures it before (and cleans up after) a hurricane; and who has first dibbs should one of the partners die or go bankrupt. (Do you want Dr. Right passing the fractional down to his "out of control and now very rich and spoiled crack-addicted son?")
(3) If you decide to go in with "friends and family," be prepared to lose friends and alienate family--prepare for the worst case scenario, chances are you'll be glad you did. Squabbles from who let their dogs sleep on the cream-colored sofa to who is going to buy new dishes and appliances when they break down, will be the highlights of family picnics and holiday get-togethers.
(4) If you've had this home for sometime and you now find that you can't afford to keep the house on your own (because of increased carrying costs, low rentals, change in personal financial situation), or you just bought this house and realize you've bit off more than you can chew, you really need to sit down, do some soul-searching and re-evaluate your entire financial plan. Do you expect your financial situation to get worse, better or stay the same in the future? As hard as it might be, you really need to crunch the numbers and see if you are getting "value for money" by hanging on to this house.
(5) Realize that fractional home ownership may only be one answer to your problems---but then again....maybe it might not be the right answer.
There may very well be many, many "fractional ownership love-fests" going on in SoWal (none that I know of personally)--but as many here can attest, I'm wired to give the "other side of the story." <cue Donna>
Best of Luck