Hello, im using virtualbox and I went looking on their forums like you suggested and I came upon a post that said to use a "Bridged adapter" so I changed the network adapters to use a "Bridged" one and then I went to test the antivirus I have on the machine against the EICAR test and not a peep from avast on the host, when I wasnt using a bridged and I tried to do the EICAR test the guest os antivirus would detect it as well as Avast on my host os, so Im guessing I have achieved the Isolation ive been looking for, atleast I hope I have.