Office A has a main SQL Server. Office B has a backup SQL Server they are linked by a WAN link. The SQL Servers use a technology that will allow them to automatically fall over incase of failure. Remote offices have links to Office A via VPN. Would the remote offices need to have VPN links direct to office B so they can access the backup server in case the main server at Office A went down or could they connect to Office A and the traffic be routed through to Office B via the WAN link between A and B. Whats Best ?