Yes they can. You may create a restricted access link for any App where customers can send PNs, modify the Calendar page and see the Statistics. Here is a tutorial on the Restricted access feature: http://www.youtube.com/watch?v=5K_LNJ3gRr4&feature=plcp
Actually it does work, the video is outdated but the features and links are still there. I just tested it on the browser and it works and I know the preview app works, because I use it often. If you can't figure it out perhaps try the online chat support.
Hello Rick ill do that i tried gain but get nothing going back to my page you say video outdated is there anything that is up to date were to i get more learning curve i plying around with my pp now its not important app im learning different things with the dashboard and stuff