From what you described, looks like the AVB network is routing all traffic to the 32SX because it is the monitor; the default AVB setup (w/Presonus) will setup the "monitor" console as the routing "hub" for the network.
You may have success with that setup if you set the 32SX as a "stand-alone". In reality, the 32SX is not working as a monitor, but more as a "broadcast" console. This will not impact the other consoles (or their assignments).