my %newTrailsToCombine =  (
          'a|b' => 'a|b|c|d',
          'b|c' => 'a|b|c|d',
          'c|d' => 'a|b|c|d',
 
          'j|k' => 'j|k|l|m|n',
          'k|l' => 'j|k|l|m|n',
          'l|m' => 'j|k|l|m|n',
          'm|n' => 'j|k|l|m|n'
          );