# pay attention to windows doublequote around the oneliner, on Linux is perl -e '...' not perl -e ".."

perl  -MData::Dumper -F";" -lane "BEGIN{$f=1};$f?$hoh{$F[1]}{$F[0]}=[]:push @{$hoh{Wood}{$F[2]}},$F[0];$f=0 if eof; 
                                  END  {print Dumper \%hoh}" file-1.txt file-2.txt                                  
                                

$VAR1 = {
          'Wood' => {
                      'NASSAUCOUNTY' => [
                                          '920232',
                                          '727659',
                                          '471817',
                                          '983043',
                                          '578286'
                                        ],
                      'SUWANNEECOUNTY' => [
                                            '640802',
                                            '403866',
                                            '828788',
                                            '751490',
                                            '972562',
                                            '367541',
                                            '481360'
                                          ],
                      'CLAYCOUNTY' => [
                                        '119736',
                                        '448094',
                                        '206893',
                                        '333743',
                                        '172534',
                                        '785275',
                                        '995932',
                                        '223488',
                                        '433512'
                                      ]
                    }
        };