如何根据给定标准对嵌套集合进行分组？

def group_nested_collections(nested_list, group_size):
    if not nested_list:
        return []

    if isinstance(nested_list[0], list):
        return [group_nested_collections(sub_list, group_size) for sub_list in nested_list]

    return [nested_list[i:i + group_size] for i in range(0, len(nested_list), group_size)]

nested_list = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
group_size = 2
result = group_nested_collections(nested_list, group_size)
print(result)