The wording for Destination Exchange is that you cannot use the week for commercial gain. The wording is:
"Reservations Made for Commercial Gain
Reservations cannot be made for commercial gain. Destination Xchange has been created for the enjoyment of all members. Reservations made solely to sell or rent, for a profit or significant financial gain, are not permitted. If such practices are discovered, we reserve the right to cancel those reservations and may suspend the membership."
If you are "renting" it out for your costs, it is okay according to the Destination Exchange wording. This is on page 14 of the Destination Exchange Guide. You are not making a "profit or significant financial gain." So it sounds okay to do. The wording is different with all the different companies - but given this wording, what you are asking about doing is okay within Destination Exchange's written policies.