NIM w/ two network interfaces

Hi all, this is my first post on this forum. My main problem is this:

I have a NIM server that I am trying to configure two interfaces on. One interface is for an internal Admin VLAN, the other is so that the server can use SUMA to pull updates. The problem is that I need help w/ the routing. I have made a few mistakes doing this. I want to force all 10.x.x.x traffic over the Admin VLAN and everything else can go over the interface. That way all of the other AIX boxes and admins can come in on en4 and SUMA and all other packets go to the en8. I used route add and when i rebooted I lost all of my routing, I know that it isn't persistent now! I have used smitty to do a lot of the changes the problem w/ that is that it puts multiple entries into the ODM. Not good messes up the routing table. Here is what I have right now:

Route Tree for Protocol Family 2 (Internet):
10/8 10.156.40.1 UG 5 3660 en4 - -
10.155.40.0 10.155.40.16 UHSb 0 0 en8 - - =>
10.155.40/24 10.155.40.16 U 0 1 en8 - -
10.155.40.16 127.0.0.1 UGHS 0 1 lo0 - -
10.155.40.255 10.155.40.16 UHSb 0 4 en8 - -
10.156.40/24 10.156.40.20 U 1 107459 en4 - -
10.156.40.20 127.0.0.1 UGHS 5 77 lo0 - -
10.156.40.255 10.156.40.20 UHSb 0 4 en4 - -
127/8 127.0.0.1 U 13 171177 lo0 - -

I just need to force all 10.x.x.x over the internal en4 interface, shouldn't be that hard right? Yet I need both interfaces to know where their default gateways are... Maybe I am just missing a step, that is what I am thinking. Any help would be great.