http://books.google.com/books?id=uV8LAAAAQBAJ&pg=PA77&lpg=PA77&dq=dslr+select+folder&source=bl&ots=iZvnVRvTgn&sig=EvNzG_dCtc9iWlo8HPLGPxTVWLM&hl=en&sa=X&ei=BJryUY-WM4jIiwKV1oCICQ&ved=0CC0Q6AEwAA#v=onepage&q=dslr%20select%20folder&f=false and page up a little and you see you can set the folder.

Frankly I think this would get a little tedious and could tell what groups there are by the old school slate board at the beginning of the shoot. If you haven't seen one, here it is.

-> https://www.google.com/search?q=movie+slate&oe=utf-8&aq=t&rls=org.mozilla:en-US:unofficial&client=seamonkey-a&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi&ei=xZryUeOZF4bBigKwy4CIAw&biw=1366&bih=608&sei=zZryUa-lO8mLiwL0kIDABA
Bob