Create small network with 4 hosts - block all outbound/inbound except internet

Hi,

I have 4 Windows servers. 192.168.4.4-7.

I want full access between all four. But everything else in our network, 192.168.* and 172.* should not connect to them.

So I want all four of them to be isolated except RDP from one computer.

I also want them to be able to connect to internet.

The reson is that I want to test AD/Exchange disturb anything in our network.