Multiple ADSL routers problem

Hi,
I'm developing a server application under WinXP that needs to accept incoming connections from multiple ADSL routers.

Right now, I'm trying with 3 ADSLs and 3 NICs. Each router is connected to one NIC, both in the same network range, and different from the two others. Each NIC has the default gateway configured to the corresponding router, so all works more or less fine... (more or less because sometimes the gateways dissapears from the configuration... and I have the DeadGatewayDetection disabled in the registry )

What I want to do, is to have all the routers connected to only one NIC. I've tried giving the 3 IPs to the only NIC (maintaining the differents subnets) and the 3 gateways, but this only works sometimes and only with 2 routers (randomly, only 2 works and the 3rd not). The problem seems to be that the connection enters the router and reaches the NIC, but then, the PC uses other different gateway to respond (sometimes uses the right gateway, sometimes not, so it seems to be choosed randomly as all the routers are the default routers)

Also, sometimes (more frecuently than with 3 NICs) the gateways dissapears. I forced the gateways using static routes for 0.0.0.0, but it is the same.... ipconfig says the gateway in not present while route print says yes.

The incoming connections are from random IPs, so I can't make static routes....

Please, someone has any clue for this headache?

Any help will be wellcome.

Thanks in advance

Try bridging the connections...