So you have a HomeGroup established and you want to block a folder so that no one in your Windows 7 HomeGroup can view it. With HomeGroup, you don’t have to worry about all the complicated permissions dialog boxes that you have to hassle with in regular networks. Windows 7 makes it just as easy to block individual folders as it is to add them to your HomeGroup. There are two easy ways to block access to folders to your HomeGroup, depending on where the folder is.
If the folder is in your Public Documents folder, everyone in the HomeGroup has full access to it. To block your folder, just move the folder out of the Public Documents folder and over to a private part of your computer.
If your folder is in one of your shared libraries, you can still block it individually. When you block a folder this way, no one in the HomeGroup will be able to open the folder:
Chose Start→Computer and then select the Library where the folder is located.
Navigate to and select the folder you want to block from the HomeGroup.
On the menu bar, click the Share With button and choose Nobody.
If you “Share With Nobody,” nobody but you can get into the folder — even if it’s sitting inside a shared library.