use Graph::Directed;
  my $network = Graph::Directed->new();

  # Build a directed network of partners and members
  foreach my $partner ( keys %partners ) {
    foreach my $item ( @{ $partners{$partner} ) {
      # Add each pairing as a network edge with weight 1
      $network->add_edge( $partner, $item );
      $network->set_attribute('weight', $partner, $item, 1);
    }
  }

  # Now build a shortest-path network
  my $friends = $network->APSP_Floyd_Warshall();

  # Now review all of the links in the network
  my $required_level = 2;
  my ( @all_levels ) = $friends->edges();
  while ( scalar @all_levels ) {
    my ( $from, $to ) = splice(@all_levels, 0, 2);
    my $degrees = $friends->get_attribute('weight', $from, $to);
    next if ( $degrees > $required_level );
    push @{ $allmembers{$from} }, $to;
  }