You will want to go back to the front desk a day or so after setting this up and get a list of all charges to ensure they are getting split out correctly.
I agree with this. The folks at the front desk will tell you that you can set up separate cards for eachmagic band, but it doesn't always work correctly. Be warned!
When I shared a room with my friend a year ago, we each set up separate credit cards, with separate PINs, linked to our magic bands. When I checked at the end of the second day, I found out that all of my charges were going to my friend's card. I asked them to separate them out manually, which they did. Checked back at the end of Day Three, and they were still charging all of my things to my friend's credit card. Once again, they separated them out one by one, at my request.
At that point I gave up. I wasn't willing to spend 20 minutes each night at the front desk while they separated out the charges. Plus, it's my understanding that when your room charges reach a certain dollar limit, they (Disney) automatically charge your credit card on file, starting you back again at zero. I think it's $500 for value resorts, so I didn't want my friend to have to pay for my charges, then have to reimburse her afterward. Luckily, they were able to identify hose charges were whose (due to separate magic bands).
So you can sure give it a try, but be sure to check early on (ideally at the end of the first day) to see if it's working!