gal

Hi all, I'm trying to implement the following scenario: I would like to share a folder with my friends/family where everyone have the permission to add content (as with master secret), but deletion is made locally (per user) only. As an example, I'll be sharing pictures with my family and they will do the same. When I delete content, whether I was the one who originally posted or not, I only effect myself - pretty much like public Torrents. Can this be achived? if so, how? Thanks