my $ranges = [
    { I => "2", },
    { I => "3", J => "2", },
    { I => "4", J => "3", K => "2", }
];

my $array; ## The name is a lie!!

foreach my $rvarHASH ( @{ $ranges } ) {
    my @rvarLIST = sort keys %$rvarHASH;
    my @orderedIndices = @{ $rvarHASH }{ @rvarLIST };
    my $array->{ join ';', @orderedIndices } = $netlist;
}
## Err...That's all folks!