Hi Liam,
I think you could do something like this in RailClone by controlling the randomisation of a segment in the Start and End inputs. By wiring the stones to a Selector operator you can set the randomisation to Generate on Y Row to ensure the start and end geometry are always the same. You can then use negative padding to clip the start and end, in my example I've randomised this value too.
This is an interesting question that I might explain in this Thursday's livestream on YouTube.
Thanks,
Paul