Security on File Folders

Security on File Folders
I have Folder-A containing subfolders Folder-1, Folder-2, Folder-3, Folder-4

How can I secure Folder-2 to be viewed by certain
users while providing the capability for all other users to view Folder-1, Folder-3, Folder 4
via Explore etc..

Any help would be appreciated.
Thanks.
Ed. Majerczak