Yes, in principle it is possible to adopt this kind of policy in the network controller. It can even be a policy which is applied specifically by end-device, meaning that a pool of end-devices could be acknowledged on Rx1, and others on Rx2.

The network server and application server are software entities that control higher level aspects of a LoRaWAN application. The gateway and end device look after the physical layer connection, the network server looks after the protocol and the application server looks after the application level control and data. All are required.

Any LNS which implements the LoRaWAN backend specification can register to the Semtech Join Server. The list of registered network server can be obtained via the Join Server Web Portal. 

Semtech Join Server allows to register any new Network Servers via the Join Server Web Portal. Create an account on LoRa Cloud, click on ‘Your Network Server’ and ‘Add Server’ to generate your access credentials for the LNS-JS interface to the Semtech Join Server according to LoRaWAN Backend Specification.