hi @Federico.Stefanato , briljant!
The use case is a calculation in which I need to check if a bus that arrives (for example in Brussels) is in time to operate a second line. The trip (i.e. Amsterdam → Brussels via multiple stops) is trip 1, while trip 2 is Brussels - Amsterdam via Antwerp, Rotterdam, The Hague etc.
I was on the outlook for a way to define the trip as a number to get the the value of a minus one (thus for line 3 we look if line 2 arrives in time and for line 2 we look at line 1).
Since I am dyslexic I cannot relay so much what I see, I need to calculate the outcome in case the question is how many buses and drivers we need to execute two lines.