Getting each file name as a field when reading several files in Microsoft Excel input

Hi!

So I have a folder with files from different sources that I need to combine and process.
They all share the same field structure and name convention, so I am using one single input step and a regular expression to read them all.
But the problem is that I need to identify the source of each line, and there is no way to know where they come from once I append them.
Having one step per source is not an option because there are many sources and they vary from day to day.

Example:
I have these files:
That have this structure:
And I want to read them with one single step and get something like this:
Is there a way to do this?


Thank you