basic LAN configuration help

hello,

I have a set of 5 static IPs and I would like to have two of them assigned to two different (physical) machines that will be running various services I need publicly available (http, ftp, ssh, etc.).
I would also like each machine to be able to talk to the other on the LAN (e.g using local subnet address of 192.168.1.2, etc.).
Each machine is running a debian flavor of Linux.

The provided modem/router is the SMCD3G model.
If I connect via ethernet directly to the SMCD3G and configure the machine's network settings with one of the static IPs, that machine is reachable on the Internet.

Since I want > 1 machine on a LAN communicating with each other + publicly available, I have introduced my own router (a Netgear WNR1000) but quickly have hit a wall in understanding how to configure this.

The SMCD3G (I believe) has been set at the least restrictive state - e.g under Firewall | Port Configuration, the "Disable all rules and allow all inbound traffic through" is checked, and "Disable Firewall for True Static IP Subnet Only" is checked".

I have the Netgear connected to the SMCD3G, and within the SMC3DG console I've tried 'Static Routing', 1-to-1 NAT, and enabling a DMZ all with no luck (the machine attached to the Netgear can get out to the Internet but nothing can reach it from the outside).

There is some critical step I must be missing - any advice or pointers to documentation (if it exists) to do this would be greatly appreciated.
I did not anticipate this being so difficult.

thanks