Check whether file is processed in a control file list

I've a list of files which got processed in Target table A and stored in a control file(list of control files).
I've want to trigger another process (later) based on this list of files and load into Target table B and continue running this process until this file list is exhuasted.
How do I come to know whther there are no more files to process in 1st process so that I can trigger the 3rd process(which will extract data from B into a file and ndm).

Thanks
Manoj

What have you tried so far? Pls post sample data as your data structure is not clear.