Static IPs behind ICS/Router/Firewall?

Q: set up Static IPs on LAN systems behind single point of net contact

[WyvernHall]

I've been researching how to do a local network expansion and am still not entirely sure how to go about doing this -- any direct help or leads in the right direction would be appreciated. :)

Here's what I have now:

cable 
¦ 
cable "modem" 
¦ 
ICS/Router (PC A w/public IP) 
¦ 
Switch 
¦¦¦¦ 
LAN (PC B-E w/private IPs) 

PC A runs WinME, ICS, firewall, and webserver, static public IP

PC B-D occasionally run various other servers using port forwarding via PC A & ICS configuration

What I want to do is obtain additional static IPs and set up something like this:

cable 
¦ 
cable "modem" 
¦ 
ICS/Router (PC A w/public IP) 
¦ 
Switch == LAN (PC B-C w/public IPs) 
¦¦ 
LAN (PC D-E w/private IPs) 

PC A to run WinME, ICS, firewall, and webserver, static public IP

PC B-C to run Win2K, webservers using static public IPs via PC A routing

PC D-E continue as before with private IPs using ICS for internet access.

Here are my questions:

Can PC B-C use the ICS gateway (192.168.x.1) or do I need to define it using PC A's public IP?

Do I need to establish a persistent route on PC B-C via route.exe for them to figure out how to reach the internet or will this happen automagically?

Does my ISP/cable company need to establish persistent routing through PC A's IP to reach PC B-Cs IPs?

Can all three static IPs be in the same subnet or do PC B-C need to be in a subnet different from PC A?

Would it be advantageous to continue to provide private IPs to PC B-D and bind the public IPs to PC B-C as additional IPs?

Am I barking up the wrong tree entirely?

(FWIW, I know how to set this up using a different configuration --

cable 
¦ 
cable "modem" 
¦ 
Switch == (PC B-C w/public IPs) 
¦ 
ICS/Router (PC A w/static IP)  
¦¦ 
LAN (PC D-E w/private IPs) 

-- but I'd prefer to keep all systems on the LAN, behind a single point of internet contact if possible.)

[DaveAtIFG]

We're pleased you decided to join us at WebmasterWorld WyvernHall! Welcome! :)

Although I understand most of your questions, answering them is beyond my experience. Personally, I'd probably apply the KISS principle and go with the last configuration you mentioned, but the "single point of contact" is much stronger from a security aspect. Fortunately, we have quite a group of pros with extensive experience in all areas. And they're very generous about helping others!

How 'bout it guys... Ideas for Mr. WyvernHall? :)