playing with hyper-v

Since I almost deal exclusively with small and micro businesses, I haven't had a lot of virutalization experience.  And I started playing with them on a Hyper-V test server.  I started off with a lot of AD and win7/8 stuff.  Now I am looking to do some WAN stuff.  I have a 5 WAN IPs, with one in use already on my own network.  I would like to use one of the other WAN IPs for use with the virtual network I have but am not 100% sure how to keep them separate.

I have them on their own virtual switch, which is ran off a second NIC on the server, which is physically connected to my current subnet. 192.168.1.x .  The test machines arein their own subnet with 192.168.102.x AND their own hyper-v vlan, ID 2.  Then I also made a virtual Untagle box that is the gateway for 102.x as well as dishing DCHP.  So far all of my vms in the 102 pick up DHCP from the correct server.  Right now the virtual router has an internal IP connected to my network on its WAN, which I would like to change to one of the WAN static IPs, then a second NIC that is the gateway for the 102.x

I see there is a "allow management operating system to share this network adapter"  If I disable that, will that effectively separate my 1.x network from my test vlan 102.x?  Can I now simply give my virtual untangle External link the WAN IP? and connect it directly to the WAN switch? I hope all this makes sense...