我尝试用**array_merge（）将两个数组数据相加。它只是附加到后面。但是较低的级别被忽略。
有没有替代array_merge（）**的方法可以合并user值而不复制color值？
现有阵列数据：

$existingtArr = [
    "A" => [
        "color" => 'red',
        "user" => [
            "Daniel" => ["01:18:08", "04:10:12"],
            "Max" => ["01:04:00"],
            "Serto" => ["02:00:02"],
        ]
    ],
    "B" => [
        "color" => 'blue',
        "user" => [
            "Franz" => ["08:40:52"],
            "Hugo" => ["07:08:58"],
        ]
    ]
];

新阵列数据：

$newArr = [
    "A" => [
        "color" => 'red',
        "user" => [
            "Fabian" => ["06:03:00"], // + 1 user
            "Max" => ["04:10:12"], // + 1 new time 
            "Serto" => ["02:00:02"],
        ]
    ],
    "B" => [
        "color" => 'blue',
        "user" => [
            "Franz" => ["08:40:52", "14:05:32", "20:34:15"], // an older one is available, + 2 new times
            "Hugo" => ["04:10:12"], // + 1 time
        ]
    ],
    "C" => [ // + new whole group
        "color" => 'green',
        "user" => [
            "Maxi" => ["07:08:58", "04:10:12"],
        ]
    ]
];

用新数据补充现有数据：

echo '<pre>';
print_r(array_merge($existingtArr, $newArr));
echo '</pre>';

预期结果数组数据：

$resultArr = [
    "A" => [
        "color" => 'red',
        "user" => [
            "Daniel" => ["01:18:08", "04:10:12"],
            "Fabian" => ["06:03:00"],
            "Max" => ["01:04:00", "04:10:12"],
            "Serto" => ["02:00:02"],
        ]
    ],
    "B" => [
        "color" => 'blue',
        "user" => [
            "Franz" => ["08:40:52", "14:05:32", "20:34:15"],
            "Hugo" => ["07:08:58", "04:10:12"],
        ]
    ],
    "C" => [
        "color" => 'green',
        "user" => [
            "Maxi" => ["07:08:58", "04:10:12"],
        ]
    ]
];