my @keys = ( qw|a e i o u| );
my @records = ();
push @records, '1|2|3|d|4';
push @records, '1|2|3|a|4';
push @records, '1|2|3|d|4';
push @records, '1|2|3|o|4';

my @final = ();
my @result = ();
my $re = '';
foreach my $key ( @keys ) {
    @result  = grep{ m/^\d\|\d\|\d\|$key\|\d$/ } @records;
    push @final, [ @result ] if @result;
}
print map{ "@{ $final[$_] }\n" } 0..$#final;