communicate guests on different hosts with out using bridged network

Hi All,

How to establish a communication between 2 vm's which are on different host machines with out using bridged network..

Explanation

VM1 ->> The machine which is running on Windows Server 2008 R2 with a ADDS and DNS which is on some test domain (let me say javis.local)

VM2->> another 2008 R2 server with IIS  and some other applications (javis.local)

VM3 ->> a windows xp machine.

VM1 and VM2 are the Host1

VM3 is on host2

VM1 and VM2 are 10.10.10.x network

Host1 and host 2 are on the 192.168.10.x network..    which is on some other domain (let me say conteso.net)

Now, my requirement is - I want to make a communication between VM1 and VM3, which intern can access VM2

I do not want do a bridged network, for the very reason, all these should not be on the same network

any inputs will be greatly appreciated..