Untested:

my %info;
while (<>) {
    my ($key, $value) = /([^|]*\|[^|]*)\|(.*)/;
    push @{$info{$key}}, $value;
}
while (my ($key, $value) = each %info) {
    local $" = ",";
    print "$key|@$value\n";
}
__END__
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