#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11132513
use warnings;

my %hash;

while( <DATA> )
  {
  my ( $top, @rest ) = split /,|\n/; # FIXME faking CSV for testing
  $hash{$top} = chain(@rest);
  }
use Data::Dump 'dd'; dd \%hash;

sub chain { return @_ > 1 ? { shift() => chain(@_) } : shift(); }

__DATA__
a,b,c,d,e
f,g,h,i,j
xx,yy,zz
this,is,a,strange,type,of,data,organization

##</code><code>##

{
  a => { b => { c => { d => "e" } } },
  f => { g => { h => { i => "j" } } },
  this => {
    is => {
            a => { strange => { type => { of => { data => "organization" } } } },
          },
  },
  xx => { yy => "zz" },
}