[am508]

I have to create a specific route for each NAT host on each node in my cluster.

I'm running linux so your mileage may vary on the process below

Login with admin rights
Type sysconfig
Select the Routing option
Select the Add New Host option
In the Destination IP field insert your external IP
In the Gateway IP field insert your hosts internal IP
Hit <CR> for the metric field

Hope this helps...