Data line numbers

Is there a data extractor property that will give me the location of text data relative to the original input pages?
I have data where each input page contains a header + details + footer.
After I set the boundaries to split by customer, I have something like this
header, details, footer, header, details, footer, header, details, footer
and I want to put all those details into a detail table.
The details have no convenient marker to aid recognition, but I do know they are all between lines 13-50 on the original input data pages.
Is there a property that would give me the location on the original input pages? It looks as if this info is lost, once the set boundaries have been determined.

Could you add more infos?

For what I am gathering, your data format input is line printer?
Now you wan to know on which line, data comes from?

Can you give a screenshot of the data?

Maybe it would be better to open a technical ticket on our website, so a technician can look at it and reproduce the issue?

In this case I have found enough reliable data in the header and footer to constrain the detail lines.
Failing that, the only idea I have that would work is to run a preprocessor step that would prepend each line with its line number in the original data file.
I assume that there is no built in method of retrieving the original line numbers. That was the point of my question.

Nope, there is no native way to retrieve the original line positions.