#!/usr/bin/perl
use strict;
use warnings;


while (<DATA>)
{
    process_record ($1) if /^\s*START\s*(\w+)/;  
}

sub process_record
{
   my $start_value = shift;
   my @record;
   
   my $line;
   while (defined ($line=<DATA>) and $line !~ /^\s*END/)
   {
      push @record, $line;
   }
   my ($end_value) = $line =~ /^\s*END\s+(\w+)/;
   
   @record = map{"$start_value $end_value $_"}@record;
   print @record;
   print "\n";
}

=prints
abc xyz MAY 
abc xyz JUNE 
abc xyz JULY

oue 2345 MAY 
oue 2345 JUNE 
oue 2345 JULY
=cut


__DATA__
START abc
MAY 
JUNE 
JULY
END xyz
blah
....more blah...
START oue
MAY 
JUNE 
JULY
END 2345

##</code><code>##

  # @record = map{"$start_value $end_value $_"}@record;
  # print @record;
  print "$start_value $end_value $_" for @record;