NAT nodes out to the Virtual server VIP

I have a couple of different Pools that need to NAT out to the VIP of their corresponding Virtual servers VIP, only when making connection out to the internet. I don't want to NAT them when connecting to internal ( RFC 1819) addresses.

I have created a SNAT rule and applied to the Virtual server that the members are associated with, it will NAT the connections for both external and internal connections.

I do have a Virtual forwarding server, I am wondering if this is where I need to create the SNAT pool, and if so how would I setup the rule..

A quick diagram of what i have and I am trying to accomplish..

Node 1(172.24.X.1) ---->

   ------> Pool members >>>>>V_S 127.0.0.1 (Need to  NAT out bound connections to this IP) 

Node 2( 172.24.X.2) ---->

////////Second Pool of server //////

Node 3 ( 172.24.X.3) ---->

      ------> Pool members -> VS127.0.0.2 (Need to NAT out bound connections to this IP) 

Node 4 ( 172.24.X.4)---->

////////Internal Connections///

Node 1 ( 172.24.X.1) ---->

Node 2 ( 172.24.X.2) ---->

------> members >>>> VS_Forwarding_server (do not NAT internal connections to 172.16.0.0/12)

Node 3 ( 172.24.X.3) ---->

Node 4 ( 172.24.X.4)---->

Thank you