Segregating WAN traffic to provide public internet access from a central location
We provide wireless internet in public areas in every office. For this purpose we provide cable internet, DSL, or dedicated T1 circuits. To save money and better control this traffic, we want to direct that traffic back through our headquarters' internet circuits. To do this we need a way to segregate this traffic on our WAN links for security and to keep it from overutilizing our WAN.
VRF and tunnels seems to be the answer.
Cisco Design Guide