So while in my IIS root directory (c:\\inetpub\\wwwroot) I\'ve created a symlink to a network drive using:
mdlink /D truthuniversal \"U:\\Truth Universal Full Site\\
I agree that virtual directory in IIS may be what you want, but if you want to minimize IIS maintenance, consider this:
Instead of directory symbolic link: mklink /D
try directory junction: mklink /J
This worked for me and the web apps are able to write to the same directory.
mklink /J App_Data d:\shared\App_Data
worked for me on Windows Server 2008 R2.