Excluding pivot rows in Eloquent ORM query - laravel

Question

(laravel 4.2)
There are four tables involved; users, posts, flags, and post_flags.
I want to retrieve every post a certain user has, and retrieve the flags set for the post, but only the flags that are set by the user in question.
For example: A post can have flags: 1,2,2,3 where flag 2 is set twice. Once by User A, once by User B. I don't want to see the flags that User B has set.
The Eloquent query in my controller:
$posts = Post::whereHas('companies', function($q) use($company_id) {
$q->where('id', '=', $company_id);
})->with('flags')->get();
The Relation in my Post model:
public function flags() {
return $this->belongsToMany('PostFlag', 'post_postflags', 'post_id', 'flag_id')
->withTimestamps()->withPivot('owner');
}
How would I achieve this using Eloquent ORM?
UPDATE
My final query, thanks to andrewtweber:
Final query
$posts = Post::whereHas('users', function($q) use($id) {
$q->where('id', '=', $id);
})->get()->load([
'flags' => function($query) use($id) {
$query->where('owner', '=', $id)->orWhere('owner', '=', 'SYSTEM');
}
]);

Answer 1

Use wherePivot
http://laravel.com/api/4.2/Illuminate/Database/Eloquent/Relations/MorphToMany.html
$flags = $post->flags()
->wherePivot('user_id', '=', $user_id)
->get();
Or with eager loading
$posts->load([
'flags' => function ($query) use($user_id) {
$query->wherePivot('user_id', '=', $user_id);
}
]);