Foldershare Works Well (Score 2, Informative)

Check out foldershare: https://www.foldershare.com/

We use it to share Pics and Vids and Music. You just have everyone create a folder on their drive, then give each account permissions. They drop stuff in the folder and eveyone gets a copy via P2P. It's a bit of a pain to setup initally, but a snap to use once it's running.