Below example works for me : x.x.x.x Server 1 y.y.y.y Server 2
flow exporter NETFLOW-EXPORTER1
destination y.y.y.y
flow exporter NETFLOW-EXPORTER2
destination x.x.x.x
flow monitor NETFLOW-MONITOR
record NETFLOW-RECORD
exporter NETFLOW-EXPORTER1
exporter NETFLOW-EXPORTER2
interface GigabitEthernex/x
ip flow monitor NETFLOW-MONITOR input