More efficient method to share folders/files

The current method of sharing folders is painfully slow, especially if you have a group of users where only certain users get access to certain folders. You have to go person-by-person to add, delete or change the type of access. Each time you submit, it takes several seconds to update one user. It is especially cumbersome when the members change frequently (people leave/join a group.) 

I suggest a "bulk" or "batch" method of changing sharing of folders using checkboxes or buttons. 

When you click on the share icon for a folder, it would bring up a popup window showing all existing share members, their options, and the ability to change attributes, and add new members. Here's a sample view of the window. The same technique can be used for files too.