I have done what you seek to do using VNC. First read up on WinVNC(search google). Pay attention to the use of TCP ports. Then install TightVNC (search google), which is an improved version. From SME, Port Forward TCP 5900 to machine1 ip address and TCP 5901 to machine2 ip address. Configure VNC on machine1 to use the default display number which is 0. Set machine2 to use display number =1. The system with display number=0 is listeing on port 5900. Display number1 listens on 5901, display #2 listens on 5902, etc.
To reach your first machine from work, open the VNC viewer, and enter the host name or IP of your SME server at home. For machine1, use the default display 0 by not typing anything after SME host name or IP address, or you can enter it after the IP or host name like this "host.sme:0" or 213.22.34.2:0. For default setting, 213.22.34.2 is the same as 213.22.34.2:0
To connect to machine2, enter "host.sme:1" or the IP address:1. READ READ READ on the WinVNC site. VNC is a great free program and is easly to configure through SME with port forwarding.
For more security, first connect to your SME with IPSEC or PPTP VPN. If you do VPN instead of Port Forwarding, you do not have to use different display numbers with VNC as you are directly connecting to the machines IP address, but it will still work if you assign display numbers, you just have more numbers to remember.