I am planning to setup a small WISP system to serve 2 small communities. Site A will have internet connected to two different ISPs. I am planning to have a PtP link to Site B. Site B will only have Internet from one ISP, maybe we will add another later on.. Is it possible for the two sites to share their Internet connection through the PtP link, and if possible how and what is required? What is this type of configuration called?