Excel VBA中的多维关联数组

Question

我试图在Excel VBA中创建包含这样的数据的变量＆＃39; php＆＃39;

$classroom['group1']['sub_group1']['John']['math']['pretest'] = 20;
$classroom['group1']['sub_group1']['John']['math']['posttest'] = 50;
$classroom['group1']['sub_group1']['John']['science']['pretest'] = 26;
$classroom['group1']['sub_group1']['John']['science']['posttest'] = 45;

$classroom['group1']['sub_group1']['David']['math']['pretest'] = 40;
$classroom['group1']['sub_group1']['David']['math']['posttest'] = 44;
$classroom['group1']['sub_group1']['David']['science']['pretest'] = 15;
$classroom['group1']['sub_group1']['David']['science']['posttest'] = 17;

$classroom['group1']['sub_group2']['Kate']['math']['pretest'] = 15;
$classroom['group1']['sub_group2']['Kate']['math']['posttest'] = 30;
$classroom['group1']['sub_group2']['Kate']['science']['pretest'] = 26;
$classroom['group1']['sub_group2']['Kate']['science']['posttest'] = 40;

$classroom['group1']['sub_group2']['Alice']['math']['pretest'] = 14;
$classroom['group1']['sub_group2']['Alice']['math']['posttest'] = 35;
$classroom['group1']['sub_group2']['Alice']['science']['pretest'] = 28;
$classroom['group1']['sub_group2']['Alice']['science']['posttest'] = 42;

echo json_encode($classroom);

我希望它的结果应该是层状结构，如下图所示

here

我尝试使用字典，但我的数据有重复密钥。

我应该怎么做才能得到我想要的结果以及我应该使用什么样的变量类型？

谢谢。