belongToMany association - can not save _joinData

Need Help
1

I have a form that submit many Entities level at the same time, so prepare request Data array by HTML form is too much trouble.
The Entities associations is at below:
Users --> hasMany --> Pupils --> belongToMany --> Courses

I patch Users entity like this:

$user = $this->Users->newEntity($userData, [
                    'associated' => ['Pupils' => ['associated' => ['EduHistories', 'Courses']]]
                        ]);

I posted request data like this:

posted user data
posted user data814×387 7.43 KB

But my entity after try to save is:

saved user
saved user829×599 14.5 KB

I am sure that my Users->Pupils->Courses can be saved because the previous code already did that, via approach of linking Pupils and Courses.
Since I added Payment_Method and Payment_Option into the join Table, I have change the code to patchEntity with associated fields, and the whole thing fail.

My PupilsTable has association as below:

$this->belongsToMany('Courses', [
            'foreignKey' => 'pupil_id',
            'targetForeignKey' => 'course_id',
            'joinTable' => 'courses_pupils',
            'through' => 'courses_pupils',
            'saveStrategy' => 'append',
]);

And my Courses has association as below:

$this->belongsToMany('Pupils', [
            'foreignKey' => 'course_id',
            'targetForeignKey' => 'pupil_id',
            'joinTable' => 'courses_pupils',
            'through' => 'courses_pupils',           
]);

My join table has associations as blow:

    $this->belongsTo('Courses', [
        'foreignKey' => 'course_id',
        'joinType' => 'INNER',
    ]);
    $this->belongsTo('Pupils', [
        'foreignKey' => 'pupil_id',
        'joinType' => 'INNER',
    ]);

    $this->belongsTo('PaymentOptions', [
        'foreignKey' => 'payment_option_id',
    ]);

    $this->belongsTo('PaymentMethods', [
        'foreignKey' => 'payment_method_id',
    ]);

And of course all of my Entity class has associated as accessible.

Is there anyway that I can add _joinData into linking function Courses->links($courses, [$pupils]) ?
So that I can don’t need to patch long level entity.

Thank you for your help.