Thanks for contacting us. You can achieve that by using a Selector Operator in conjunction with the random number parameter node. The Random number generator has the benefit of being able to re-seed on either the Start, Segment, X Spline start, X Spline Segment, or Array Y Row.
By exporting and connecting to the Selector Node's index property you have a much more controllable way to randomise segments
. The same procedure can be used with the material node to match the material IDs for the start and end of a spline section. Your style would therefore look something like this:
I hope that helps, let us know of you have any other questions.