I can see if you are not familiar with this, you might not understand the simplicity.
Just replace 3 independent repeaters. Each with their own URI.
Linking them together is just a software command.
Can all be done on one computer running ASL. But you could split them up if desired.
Not sure why you would want to use a hardwired controller at all.
It does complicate things to do so.
Simply put, ASL3 is very flexible in how it can be set up.
Therefore a single ASL3 server can support multiple nodes. But in the situation you are describing, each repeater would have to have its own interface and node number.
Having an ASL server connected to the internet provides many more connectivity options, but does complicate network setup for those not used to doing it.