#!/bin/perl5

use strict;
use warnings;
use Data::Dumper;

my %data;
while (my $record = <DATA>){
  chomp $record;
  my ($fld1, $fld2, $fld3) = split /\|/, $record;
  push @{$data{$fld1}{$fld2}}, $fld3;
}

for my $fld1 (sort keys %data){
  for my $fld2 (keys %{$data{$fld1}}){
    print 
      "$fld1|$fld2|", 
      join(',', @{$data{$fld1}{$fld2}}), 
      "\n";
  }
}
__DATA__
aaa|bbb|ccc
ddd|eee|fff
ddd|eee|xxxxx
hhh|iiii|jjjjjj

##</code><code>##

---------- Capture Output ----------
> "C:\Perl\bin\perl.exe" _new.pl
aaa|bbb|ccc
ddd|eee|fff,xxxxx
hhh|iiii|jjjjjj

> Terminated with exit code 0.