I don't think so (in fact I'm quite sure you cannot). When you drag&drop components you "generate" Java source code which is compiled later when you build the job (or run in the studio). How do you expect to change the byte code at run time?
tFileList is the solution for iterating over a list of files with give filename mask(s).
If you want to break the process after a number of iterations (varying for each run), you must use tFileList to get the full list of filenames corresponding to the mask.
After that, iterate (tLoop) to proceed with each file n times where n can be fixed for each run using a context variable (with a different value at each time if you want).
Not sure that's what you are looking for as your use case come one piece at a time and is not very clear.
