Problem with route-add-cmd

[chestnut]

Dear openconnect administrator,

I wanted to add some routes when I connect to the VPN. I work on Mac OS X 
Yosemite. The example is from linux system and there isn't iproute command 
on mac. I found some iproute alternative on mac but it did not work. And 
then I change the command to mac style such as ‘route add 192.168.0.0/16 
-interface en0’or some other commands, but it's still not working.
All I want to reach is as follows. When I work in a internal network, 
sometimes I need to connect to the VPN to cross the GFW :( . I don't want 
the internal traffic going with the VPN because it is unreachable. 
Therefore I need to tell my route table to pass all internal traffic 
(192.168.0.0/16, 172.16.0.0/12, 10.0.0.0/8) through the old gateway when I 
connect to the VPN. I tried no-route but there was something wrong. Now I 
need some help to handle the situation above.
Sorry for my poor English. Hope you can understand. Thank you!

Best regards!
chestnut