Two WAN's on own ISPs need to backup to one WHS

[MetalDwarf]

I am trying to set up a backup solution in my office. Problem is I have two offices in one building but on opposite sides of the building (within wifi range) for whatever reason, one half of the building has one ISP (shaw cable) and the other half of the building has a different ISP (Telus DSL) I just bought a Windows Home Server which I would like to use to backup both office computers.

I have 2x WRT54G routers running Tomato firmware, one in each office.
There are two workstations and a few network printers etc in each office I would like to share. All the computers can currently talk to each other via WDS.

My problem is this, each office needs to use its own Internet connection. So the office connected via Cable modem needs to use that connection only. and the other office with the DSL connection needs to use that connection only. but they still need to talk together in the middle, share resources like the WHS and printers.

how can i make this work?

Currently i have everything talking but all the internet traffic is going through only one ISP

 

[Bobacus]

Second NIC in each machine, and basically have each machine connected to two networks. One internal office network, and said machines choice of internet connection.

 

[Eiolon]

I haven't owned a WRT54G in a couple of years but I remember a place I could setup static routes. I had to set it to router instead of gateway. Then I could specify static destinations for each host to a different network. The only thing you need then is to find a way to physically connect both routers into the same network.

 

[jrdonnaruma]

I would think you could just throw a pair of wireless adapters in the WHS, have one connect to one offices network, the other, obviously, to the other office network. That should make the WHS available at both locations for backup and storage

 

[MetalDwarf]

after several hours i think i got it worked out, (would have been sooner but Norton AV is a POS )

each router has its own ISP network connection, they are networked together via Wireless Distribution System (WDS) each router specifies its own range of DHCP addresses, when a computer is connected to the individual router it gets that specific routers dhcp info and seems to use the correct ISP.
the WHS shows up for both sets of DHCP addresses as well. seems to work. if anyone wants i can post detailed settings but i think this is fairly one off situation.