TL;DR - Add configuration open to make the networks behave more realistically, allowing for network traffic to be sniffed.
There's not much more to be said here. Add the ability, in configuration at least, to make all packets sniffable. So they behave more like real packets, instead of magically reaching only their intended target and nobody else. In your code listening for network events, you'd just need to check if the target address matched your modem's address. Or maybe add this feature by default to the network library, that you can enable or disable. Preferably, this would include a