Laravel 5.2, three way many too many

I want to do the following.

I have three models: User, Business, Role

They are connected as follows: Users can have many roles, and belong to multiple businesses.

Roles are predefined.

I want that each user can have different roles in different businesses. For example, in business1 the users has role sales manager, but in business2 he has role director. User can have multiple roles on same business.

User model:

public function businesses()
{
    return $this->belongsToMany('App\Business')->withTimestamps();
}

Business model:

   public function users()
    {
        return $this->belongsToMany('App\Business')->withTimestamps();
    }

Pivot table:

    Schema::create('business_user', function (Blueprint $table) {
        $table->increments('id');
        $table->timestamps();
        $table->integer('business_id')->unsigned();
        $table->integer('user_id')->unsigned();
        $table->integer('role_id')->unsigned();
    });

I add the User to the Business as:

$user->businesses()->attach($business_id, ['role_id' => $roleId]);

This should add the row in pivot table as: ['1','2','3'].

My questions are:

• Is this the right way to do this?
• How do I proceed with detach method?
  $user->businesses()->detach($business_id)->where('role_id',$role_id); This is not the correct syntax but something like this. If the user has two roles in a business (for example: 'director' and 'sales manager') on detach I want to remove just one of the roles (for example: 'director') and not all of them. I believe that running $user->businesses()->detach($business_id); will detach all roles.
• Is there a way to use the sync() method with this?

via Chebli Mohamed