Set default root folder for existing files?

My question is about the feature for adding existing files. I see in the video that the user is able to drill down through the entire WordPress file structure to get to the "uploads" folder. Is it possible with your plugin to limit access to a particular folder, or set a default starting folder, so that the user would not have the ability to access and "poke around" in anything but the ONE folder where the files are? I need to allow editors to add files to the download area, but they should not have access to all of the files in the WP tree.

I look forward to your reply