Visual Subst is a portable applications which can create virtual drives for any folders. Users may create virtual drives for folders which need to access frequently.
Some users may doubt, why we want to use this application while we can simply create a shortcut link at our desktop? This seems to be right. But when you open a “Open File Dialog” or “save file Dialog”, these shortcuts will not appear, while Virtual Drives will appear. Furthermore, you can access these 
Virtual Drives in “My computer”
To create a Virtual Drive, simply provide the directory path and choose the drive letter. After that, press the save button to save your settings. There is an option for you to apply virtual drives on Windows startup also.
I’m wondering if it’s possible to use this software on an external hard drive to separate out different folder.