Windows Server 2012 Hyper-V guest OS license?

Hello,

I’m about to install a new Hyper-V environment.

If I have 3 psychical hosts, I will buy3 WS 2012 std. Which will give me:

• 6 Virtualizations rights
• 6 WS 2012 OS (free) licenses

Now, I would like some more VM's in this environment, so... if I buy1 WS 2012 std. license, it will give me 2 Virtualizations rights!But can I also install the WS 2012 OS for (free) on those 2? or at least 1 of them??

Thanks :)