How to avoid bad root files while using hadd

Hey, could anyone let me know if there is a way to avoid bad files while using hadd function to merge several hundred root files? hadd just stops when it encounters a bad/failed job.

I think the command gives the response when you do:

% hadd --help

usage: hadd [-a A] [-k K] [-T T] [-O O] [-v V] [-j J] [-dbg DBG] [-d D] [-n N] [-cachesize CACHESIZE] [-experimental-io-features EXPERIMENTAL_IO_FEATURES] [-f F] [-fk FK] [-ff FF]
            [-f0 F0] [-f6 F6]
            TARGET SOURCES

  -a   Append to the output
  -k   Skip corrupt or non-existent files, do not exit.  <<< This option