I looked trough the Marriott's rewards rules and didn't find any explicit total limit per stay. The following rules may influence your point-earning-capabilities:

6.A member is eligible to receive points for up to two rooms in addition to the member's personal guest room as long as all rooms are reserved and registered in the member's name, and provided the member arranges and pays for them on a consolidated bill, which should be requested at time of hotel check-in.

10.Point accrual is limited to individual travel. If a member attends a convention or group meeting and individually pays Marriott directly for the room, he/she will be eligible to receive points for the stay. However, contract rooms, rooms reserved by corporations on an ongoing basis, master-billed rooms and rooms booked at the Marriott associate or friends and family rates are not eligible to earn points. Points earned from room contracts or military rates at certain overseas locations are subject to local restrictions and may be ineligible for credit. Wholesale packages and series tours booked through a travel agent are not eligible for points.

11.When a Marriott Rewards member chooses to earn points through the sales office for a group, he/she forfeits the option of earning points for his/her personal room.