Monitor sync understanding in F5 DNS SYNC GROUP

I have two data centre with big f5 dns at Location A DC and Location B DR. I want to put both the devices in dns sync group, request for resolution will come to both the big f5 dns, the problem statement is that

1) big f5 dns at location B DR should resolve the hostnames to IPs of server that are hosted in Location A as it is DC.

2) When the servers of Location A DC are down then to the servers located in Location B DR.

3) One condition is that only big f5 in Location A can only monitor the servers in that location A and same is true for B.

I understands that monitor are local to a big f5 device, will big f5 device at location B will try to monitor the servers at location A and when no reply came will mark them down or it syncs the status of servers from Location A dns and will mark them down only one Big f5 dns at location A mark them down????

I am confused any help would be appreciated.