system
7
as i said, its very hard… means you have to administer all those computers with that specific name and password…
its possible but a lot more work (since you of course have a rotating password
)
next to that the machines are on different subnets, the ADNM console doesnt detect the other subnet as far as i know, not even tru the router… 
MSI is (proven above) the way to go 