Simple network file sharing authentication

Brom your gonna want to run "MMC" If you press windows key+r then type mmc in the box then press enter a console while pop up. in the console click "file" then "add snap in" the snap in you want is labeled "local users and groups" In your small environment i would then create your own group and name it whatever makes most sense to you and then add these few users with there computer name into the group you created. After this is complete go to the folder you are trying to share and right click it then click "sharing" next click "share" and in the drop down box select the custom group you just created in MMC. You could go as far as only allowing a certain number of users to access the folder or files at the same time. A good security measure would be to not allow anymore users access simultaneously then you are wanting to allow in total to start with. I just dont want to give and more loop holes then a home network outside of a Domain controlled active directory already has. Im sure this will work perfectly for you but if not shout back at me and we will square it away. there are plenty of ways to achieve what your after here.