use IO::File;
my %files;

$files{A} = $files{B} = $files{C} = IO::File->new('> groupA.txt');
$files{D} = $files{E} = $files{F} = IO::File->new('> groupB.txt');
# etc...

for my $n (keys %emp) {
  print {$files{$n}{Org}} $emp{$n}{Emp};
  #          ^^^^^^           ^^^^^
  #     This gets the FH   And prints this to it
}

# Now close the FH's
close($file{$key}) for my $key (keys %files);