Making a network bridge with relay

Hello,

First of all: is there a way to make a network bridge on a Arduino?
Second: I have two network connections, one from the router of provider1 and one from the router of provider2. Now I want to switch between them maybe with relays over a simple web interface (I hate to walk downstairs) if the primary connection (provider0) gets lost due to connection issues to the internet.
My concept would be to get three/four ethernet modules, two of them for provider0 and provider1, then a/four/eight relays (for every copper cable inside the patchcable) which gets connected to one ethernet output.

I hope you can understand what I have written (my english is very bad) and can help me

crazy