Here is the applicable T&C text: "A Reward Certificate is good for one consecutive stay, for one standard room only, as shown on the certificate." This text can be found at Marriott Rewards Terms & Conditions. Look at rule #9.

I read this to mean that each Reward Cert is good for one room only and only good for a consecutive stay. (Note that this does NOT say that the award nights have to be consecutive. It only states that the "stay" has to be consecutive. IOW, one could have a 10 night stay where nights 5, 6, and 7 had no standard award availability, but the other nights 1-4 and 8-10 could use one 7 night cert.) Should someone want to get 2 rooms one for 4 nights and one for 3 nights, you would have to order a 3 night award cert and a 4 night award cert. A single 7 night will not meet the T&C rules shown above.

Now does this mean that there are absolutely no GMs out there that might "bend" the rules for someone especially a known, frequent customer of their hotel? Possibly. I'm sure they have "bent" rules before, but I wouldn't count on too many bending this rule.