Hi Saige,
I was wondering how you found out which group each of the data sets belongs to. I downloaded the MR data recently and can find the "Additional Information INDI" sheet, but that only gives me the encoding of different variables. I didn't get a variable sheet to find out which group each of the scans belongs to. Sounds like you found that. Can you let me know how? (i.e. do I have to construct my query in a specific way to get the variable sheet, too?). 
Cheers, 
Lena