use File::Copy;

## set up directories
my $in_dir = '/dir/main';
my @xfer_dirs = qw! /dir/dir_1 /dir/dir_2 /dir/dir_3 !;

## list of files in $in_dir 
my @infiles;

## pick a random dir to start
## so salesperson 1 doesn't get more mail when the job restarts
my $xfer_dir_index = int rand @xfer_dirs;

{
  ## create a directory handle
  local *DH;
  ## open the directory
  opendir( DH, $in_dir ) or die "ERROR: $0 - can't open dir $in_dir - $!";
  ## get a list of files
  @infiles = grep { /^\./ && -f "$in_dir/$_" } readdir(DIR);
  ## close the directory
  closedir DH;
}

for @infiles
{
  ## move the file
  move( 
    $in_dir . '/' . $_, 
    $xfer_dirs[$xfer_dirs_index] . '/' . $_ 
  );
  ## cycle the directory index
  $xfer_dir_index++
  $xfer_dir_index %= @xfer_dirs;
}

## sleep
sleep(300);