None exists, unfortunately. A buyer of timeshare in the D.R. usually signs a one page personal contract with the hotel owner, or even sometimes just with the hotel operator. He/she has no rights "in rem" ("over the thing", that is, over the property).
What does this mean? Let's assume the hotel owner has a mortgage with a bank and defaults for whatever reason. The bank will foreclose on the property and the poor timeshare "owner"would be left with no property to "timeshare" He will have a recourse vs. the hotel owner but this gentleman will by then have no money! Another situation: the hotel owner may just sell the property without mentioning the existence of timeshares.
The third party purchaser is not obligated to honor the timeshare contracts since they are not recorded on the property records.
In other countries, the timeshare owner has a recorded right over the property which must be acknowledged by all.