Connection Broker and servers

Dear All

Can you direct me to a possible solution to make a small server 2012 pool of machines?
We have 20 identical 2012 servers that my students use in class.
I will like to assign them from a Pool and not on on one basis.
(we cannot use win7, 8 , or 10. Only 2012 for education purposes)

Thanks

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Eduardo Valverde