The FOSS layout editor pcb-rnd can load a kicad layout and can export a layout in hyperlynx format, allowing a Kicad user to get to hyperlynx format.
The hyperlynx export code was written by the same guy who wrote hyp2mat.
pcb-rnd can be also invoked as a headless cli utility, allowing scripted or batch conversion with the right command line flags, so there wouldn't be too much preventing a pretty seamless solution.
Alternatively, you could look at the hyperlynx export code
to help in rolling your own implementation.