$groups = [
    ['name' => 'Group 1', 'items' => [1]],
    ['name' => 'Group 2', 'items' => [1,2]],
    ['name' => 'Group 3', 'items' => [1,2,3,4,5,6]],
    ['name' => 'Group 4', 'items' => [1,2,3]],
    ['name' => 'Group 5', 'items' => [5,6]],
    ['name' => 'Group 6', 'items' => [5]],
];

[
        [
            ['name' => 'Group 1', 'items' => [1]],
            ['name' => 'Group 2', 'items' => [1,2]],
            ['name' => 'Group 4', 'items' => [1,2,3]],
            ['name' => 'Group 5', 'items' => [5,6]],
        ],
        [
            ['name' => 'Group 3', 'items' => [1,2,3,4,5,6]],
            ['name' => 'Group 6', 'items' => [5]],
        ]
];