Network passthrough, two W5100, one ATmega?

I'm essentially trying to make a project with a built in, two port network switch. Getting a network signal over ethernet is simple enough, but how can I pass that through? Obviously can't stack two ethernet shields. I could use different pins though couldn't I? I have a bunch of pro-mini's to play around with and a big breadboard. Would I need two W5100's?

Thanks!

Elusid:
Obviously can't stack two ethernet shields.

Nothing obvious about that, and you probably could. I think it is just a matter of clipping out snd re-routing the CS pin on one, and calling it something else. Your real problems are somewhere else.

I haven't tried anything yet, I'm just wondering what the best approach would be.

What is the speed you need for this two port network switch?

I don't need gigabit. Standard 10/100 would be fine.

Ordered two of these W5100 based modules

Could anyone point me in the right direction to getting two of these hooked up to an ATmega328 based board? I'm using Pro-Mini's. I'm trying to make many devices that can daisy-chain together. Basically I need it to be a two port network switch.

These W5100 based modules using SPI

This is the connection

https://arduino-info.wikispaces.com/Ethernet