Do you need to loop? i.e. is the result of the first query required for the second query or do you just want to make multiple queries?

Thank you @ebygomm. I would like clarification on the process of collecting values ​​from the second connected segment (sometimes there is more than one connected segment) and performing multiple queries. Once completed, I select the next segment, and so on.

Whilst it’s possible to do some looping in FME, I’d nearly always choose to do looping within a python caller if it is required.

Do I have to use Python development, or are there other, simpler solutions?

In my experience, looping in FME is often more complicated than a python solution 

Just one last point, I would like to know what type of python PythonCaller uses (pyQgis, ArcPy, or FME's own library)?

Thank you in advance for your help.

I wonder if the ‘adjacent feature’ functionality in FME would be able to help here:

https://fme.safe.com/blog/2017/08/adjacentfeatureattributes-evangelist166/

Many thanks @arenscott. I think this is an excellent way to solve this issue.
I also thank @ebygomm for his suggestion, but unfortunately I'm not very proficient with PythonCaller.