Do I need BGP to route a multiplexed dual T1 connection and a cable modem connection from another provider?

I have to setup a dual multiplexed T1 with an incoming cable data line and route them so local user traffic goes out the cable line, but incoming traffic uses the Dual T's. I'm assuming that BGP is not possible because the cable company does not allow it. So I need to route everything for our end statically. What is the best way to do this? Is there a hardware recommendation that you can make that would support heavy business use and support the configuration? I've looked at the XINCOM XC-DPG50, but that seems to be for home and small business use. I need something more robust. I considered having an ethernet wic and two T1 wics coming into a Cisco router/firewall, but I am concerned about how I would address the routing. I'm assuming I will have a cable modem between the cable drop and the Cisco router. I just have no idea how any of this would handle the routing. Any suggestions would be appreciated.