3cx phone system with Mikrotik routers

I have 2 locations. Location A has 3cx phone system on it. Location B is networked with location A with 2 Mikrotik routers. I want a backup of 3cx system in my location B incase location A loses internet. I have microsoft DNS server between the 2 stores. I need someone that has experience with 3CX phone system and Mikrotik Network, and Windows server 2012. I also need backup active directory in the same location. My Active directory in my location B needs connection to location B for the network to work. i want them to be independent of one another incase location A loses internet the servers in location B will still work. i want them to be in same forest though. I don't think the active directory or DNS is setup properly.