Adding Static Routes under Windows
1) Launch Command Prompt with Administrative Rights (Select Windows Search, type “command”, right click “Command Prompt” and left click “Run As Administrator”
2) Add 2 persistent routes for 12.0.0.0 and 13.0.0.0. Depending on your use, you may need to narrow from 13.0.0.0 to something more modest like the exact IP of the service if conflicts are present.
wide route:
route -p add 12.0.0.0 mask 255.0.0.0 192.168.10.1
route -p add 13.0.0.0 mask 255.0.0.0 192.168.10.1
narrow route:
route -p add 12.48.20.220 mask 255.255.255.0 192.168.10.1
route -p add 13.48.20.220 mask 255.255.255.0 192.168.10.1