Depends,
if you are saying you want to install two UNIX guests in VPC2007 and
link them I belive the lesser problem you will have is the serial
ports. You will have major problems installing UNIX. What flavor of
UNIX are you talking about?

If you are installing Windows guests you might want to use VPC2004
instead (then Vista is out of course) because VPC2007 has a bug in the
RS232 handling that makes it erratic in behaviour inside guests. It
won't raise the receive data events properly so it will depend on the
software you are going to use inside the guest.

Otherwise it is juat a matter of having two RS232 ports on the host
and assigning each to its own guest. Often host systems nowadays do
not have COM ports, so you have to have a host with the necessary
hardware too...

Bo Berglund