for $key( map{ $_ -> [0] } sort{ $a->[1] cmp $b->[1] || $a->[2] cmp $b->[2] } map{ [ $_,(split)[0],(split)[2] ] } keys %hash )
##          ^list1            ^list2                                            ^list3                               ^list4
##                                                                                           ^^^^^^ dups ^^^^^