Windows Server 2008 R2 with Hyper-V

So I have a router that gets public IP's handed to it using DHCP for any computer I plug into the switch. What I want to know is that if I had Windows Server 2008 R2 and Hyper-V loaded with some Windows 7 VM's will they do the same thing? Or do Hyper-V VM's share the main NIC's info? -- Brad