Hi, I plan to buy a license for Bt Sync pro but I'm not sure if a signe license is enough: I have a server with a lot of pictures I want to share with a little group of friends. But each of these friend should be able to use selective sync in order to choose what he want to download or not. If I get a license for the server and share its ID with my friends, is it ok , or each of my friend need a license (and in this case I would have to find another software) to be able to use pro features ?