As from a virtual machine to open the site raised on the local server (Denver) if they (the sites) several?

And hosts to improve not a virtual machine did not try?

You need to do to in the guest OS different domain names resolved to a single IP address of the local server.
And how to do it — there are many options: raise DNS server on the host, raise DNS service in a virtual machine (although the idea of a virtual machine and so have to provide DNS forwarding), or the easiest thing is to register site1 and site2 in the guest OS /etc/hosts.