Thanks for the response. My next question was not so much about several machines at once - just about confirming that the machines will still talk to each other in the virtual environment as they do now. The network is a flat network - no vlans or anything like that so, I am assuming that if the host machine is on the same subnet or has the same subnet mask, the 2 virtual machines should, in theory still communicate, if the original 2 physical ones are no longer on. I am not experienced with this particular scenario but have created VM's for playing with.
Just wanted to be sure that the new VMs will still be part of the domain - or do they have to be re-joined, and will still be contactable via DNS as if they were the old physical machines etc..
thanks again