Yes, you just Add a new destination NAT rule. Go to Firewall > Port forwarding / NAT > Destination NAT
You can add as many as you like.
For example, if you have 5 machines behind Endian , you will need to create 5 rules.
Each rule will be the same except for the Insert IP and the Port/Range fields.
eg:
192.168.10.1 Port 3391 (This will redirect port 3391 to PC with IP address 192.168.10.1)
192.168.10.2 Port 3392 (This will redirect port 3392 to PC with IP address 192.168.10.2)
192.168.10.3 Port 3393 (This will redirect port 3393 to PC with IP address 192.168.10.3)
192.168.10.4 Port 3394 (This will redirect port 3394 to PC with IP address 192.168.10.4)
192.168.10.5 Port 3395 (This will redirect port 3395 to PC with IP address 192.168.10.5)
Then change the RDP istening ports on each of your 5 PCs
To find out how to change the RDP Listening port go here :
http://support.microsoft.com/kb/306759To connect from the Internet using RDP to one of your machines, you will need to know your public IP address (or domain name).
If you don't have a permanent public IP address, use a Dynamic DNS service like DYNDNS.
Now, if you want to connect to PC with IP address 192.168.10.3,
use a RDP client and in the box type: mydomain.dyndns.org:3393