Groups File Access is a WordPress plugin that allows to provide file download links for authorized users. Access to files is restricted to users by their group membership.

Demo:

http://urlit.me/0nXJQ

http://dapalan.com/Jl7b

http://uploadzee.com/t5

http://uploadseed.com/323

https://www1.zippyshare.com/v/THjhaAgF/file.html

https://www.mirrored.to/files/1QGMCMI2/groupsfileaccess164.zip_links