I've been successful only with having one credit card on file per room reservation, similar to what Kimberle mentioned. Even when I stop down front and tried to assign different credit cards for different people on the reservation I had no luck. No matter who on the reservation uses their magic band to charge something, it goes back to the room and shows in the
MDE app or if I stop down at the front desk. Any charges on the room reservation will hit the credit card the primary guest has on file in their MDE account, or with the front desk, when the charges exceed $1000 total, or at approximately 9pm (some stays its been about 9:30pm) the night before check out, no matter which guest made them.
You can see the purchase totals that have been charged back to a room, as well as payments and the overall outstanding bill, in the MDE app once checked in (where it shows you the room number). Its not "itemized" per transaction (so if you go to MouseGears and buy 5 things, it shows 1 transaction for the total) ... What we do is keep an eye on the balance of the room charges, and stop down to the front desk once in a while during the trip. That being said, we often use gift cards to pay off the room charges, which does require stopping at the front desk anyway.
So Maybe you can just keep an eye on the transactions, and stop at the front desk asking them to pay those charges which are yours, with your credit card as you go?