Hello, I am looking to setup a 3CX system. One feature we are looking at is failover for internal calls only. We have five locations, and they all share a single WAN and internet connection. If the WAN fails between one of the buildings, we would like that building to still be able to make calls inside that building internally (office-to-office inside the building). Does 3CX allow for this, or have a solution. Do we need a separate server at each building set to a bridge mode, where the local server could handle the internal calls, but then route to the main server for external calls? Thanks!