You figured it out that the examples are directly hardcoding a single address so are not intended to be used “as is” for multiple responders, so you’d have to build the top protocol yourself.
In case this could be of any help, I needed the same thing as you so developed an open source framework for positioning that allows to request a ranging schema from a server running Python and deploy it across multiple initiators and responders dynamically.
I did not use the 802.15.4 addressing format, but that would be easy to adapt, I went for minimal frame size with 1 byte short ids to reduce uwb transactions timings.
here some details and examples
In case your project is open source or would like to contribute to one please let me know.