[nsp] Source specific port forwarding

[Roger]

I'm needing to setup port forwarding but need to have it based on the 
public source addresses..

Port forwarding on a global level is simple...

ip nat inside source static tcp 192.168.0.1 22 interface Ethernet0 22

The above will port forward external ip to 192.168.0.1 pot 22..

I'm needing to do something like so.

public_net_a/24 port 22 -> 192.168.0.1 22
public_net_b/24 port 22 -> 192.168.0.2 22

Where different port forwarding will be done based on source address. 
Then based on said source forward it to a different internal host.

Thanks.