say more.
Are you connecting across the Internet, or simply within the workgroup LAN?
If you are connecting across the Internet, there are different methods to
achieve this, depending on the number of machines involved, and sometimes
router capabilities.
One method is to set up your "main computer" to accept incoming VPN
connections, and make a VPN connection across the Internet to the main
computer.
You can then run Remote Desktop, and connect across the VPN connection to
the individual machines by their private IP addresses.
Check out other articles in this group about Incoming Connections for lots
of details.