I'm a bit out of my comfort zone, but here goes. I us unblock.us and it seems fine. I was trying to my wife's laptop (win 8.1) share/files and printers with my desktop (Win 7). I got an error message that I had to use IPv6.
But to use unblock.us, I had to disable IPv6 and enable IPv4
You should be able to use both at the same time, I've used unblock us without disabling IP 6, but also workgroup stuff should work with IP version 4. Worst case, if the Win8 box with the resources on it that you want to share has a static IP address, you can put an entry in the hosts file for it on the Win7 box. That should help it find it.