Are you trying to do something like this?

#!/usr/bin/perl

use strict;
use Symbol;

my %hash;
my @dirs;
@dirs = qw(ONE TWO THREE FOUR);

my %fh;
for my $loop (@dirs) {
  my($from, $to) = (gensym, gensym);
  pipe ($from, $to) or die "Oops Pipe: $!\n";
  select((select($to), $|++ )[0]); # set autoflush
  $|++;
  my $test = rand 5;    # simulate processing
  print $to "$test $loop\n";
  $fh{"FROM_CHILD_$loop"} = $from;
  $fh{"TO_PARENT_$loop"} = $to;
}

for my $loop (@dirs) {
  my $from = $fh{"FROM_CHILD_$loop"};
  my $to = $fh{"TO_PARENT_$loop"};
  chomp( my $in = <$from> );
  (my $value, my $key) = split(/\ /, $in);
  $hash{$key} = $value;
  close $to;
  close $from;
}

for my $loop(keys %hash) {
  print "keys $loop => $hash{$loop}\n";
}
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The Symbol::gensym function returns a reference to an anonymous glob which can be used just like a normal file handle.

And with recent Perls (sorry, I'm not sure how recent), you don't even need to call gensym; Perl handles it automatically, so you can just say:

my($from, $to);
pipe ($from, $to) or die "Oops Pipe: $!\n";
...
$fh{"FROM_CHILD_$loop"} = $from;
$fh{"TO_PARENT_$loop"} = $to;
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