Consecutive weeks, same resort, same guest each week:
One Guest Certificate is needed. Guide needs to post a Guest Certificate on both exchanges. However, the member only pays for one Guest Certificate.
Consecutive weeks, same resort, different guests each week:
The guest for the first week needs a Guest Certificate. If a different guest occupies the same resort (or unit) the following week, a new Guest Certificate is needed.
Concurrent weeks, same resort:
A Guest Certificate for an occupant in each unit is needed. (it is not possible for the same guest to occupy both units simultaneously)
Different resorts, same guest at each resort:
One Guest Certificate for each resort is needed.