I have four offices spread over the state with different ISP's. I need to get them on the same network so they can all share files from a server in one location. I have fairly extensive LAN knowledge but WAN knowledge is very minimal. What do I need to get these connect with the least amount of cost/setup yet something reliable? The offices are all connected a little bit differently. Three have standard cable/dsl setups but one of them is piggybacking off of a T1 that is in the office complex I believe. Thanks for your assistance.