How do i separate 2 networks BUT share internet b/w the 2?

[Cytomax]

Hello all

QUESTION

Currently these networks are 100% separate but i want to share the DSL Modem between the 2 networks...

INFORMATION

Network # 1

DSL Modem

Linksys Router <-- using the Tomato Firmware

Windows 2K3 Server and 10 WinXP Pro clients

Network #2

NO DSL Modem

Linksys Router <-- using the Tomato Firmware

Windows 2K3 Server and 10 WinXP Pro clients

The only way i can join the 2 networks together is wirelessly

I DO NOT care if i have to buy a 3rd Linksys Router

POSSIBLE SOLUTIONS

I have been researching on the best way in which to share the internet across both networks without the 2 networks being able to see each other and these are my results

1) Some recommended using different ip's

2) Some recommended using different subnets

3) Some recommended using a switch between the the DSL Modem and the Routers

4) Some recommended DSL --> Router --> 2 Different Switches and i have to "BREAK" the ports or something about vlans etc.....

So what do you guys think?

Thanks in Advance

Eddie

[eyeball]

How about 2 seperate subnets with rules that forward port 80 and port 443 traffic (from the network with no internet) to the default gateway of the network with internet.