Since you are not a member, you are actually renting a reservation. If one member cannot reserve your entire stay, you will have to put your stay together by whole days - i.e, 4 days from one member and 3 days from another for a week's stay. You can only rent whole days. In other words, you can't get 4 points from one member and 4 points from another and put them together to get one 8 point night's stay.
If you do rent from more than one member, ask one of the members to ask MS to "link" the reservations so that you don't have to change rooms during your stay.
Best wishes -