c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my $major_div = '!!';
 my $user_div  = '0';
 my $var_div   = ',';
 my $full_string = join $major_div,
   'abcd-efgh-ijkl-mnop0key1=data1,key2=data20key1=data3,key2=data4',
   'qwer-asdf-zxcv-tyui0key1=data30key3=data6',
   'trew-hgfd-ytre-bvcx0key1=data7,key2=data80key1=data9,key2=data10',
   'erty-dfgh-cvbn-hjkl0key2=data50key3=data6',
   ;
 print qq{full_string: <<$full_string>> \n};
 ;;
 my $aref = fieldParse($full_string, $major_div, $user_div, $var_div);
 dd $aref;
 ;;
 sub fieldParse {
   my $source = shift;
   return $source unless @_;
   ;;
   my $delim = shift;
   return [ map fieldParse($_, @_), split $delim, $source ];
   }
"
full_string: <<abcd-efgh-ijkl-mnop0key1=data1,key2=data20key1=data3,key2=data4!!qwer-asdf-zxcv-tyui0key1=data30key3=data
6!!trew-hgfd-ytre-bvcx0key1=data7,key2=data80key1=data9,key2=data10!!erty-dfgh-cvbn-hjkl0key2=data50key3=data6>>

[
  [
    ["abcd-efgh-ijkl-mnop"],
    ["key1=data1", "key2=data2"],
    ["key1=data3", "key2=data4"],
  ],
  [["qwer-asdf-zxcv-tyui"], ["key1=data3"], ["key3=data6"]],
  [
    ["trew-hgfd-ytre-bvcx"],
    ["key1=data7", "key2=data8"],
    ["key1=data9", "key2=data1"],
  ],
  [["erty-dfgh-cvbn-hjkl"], ["key2=data5"], ["key3=data6"]],
]