I have standard Post & Comments hasMany relation

class Post extends Model
{
    // @property int $id
    // @property string $title
    // @property string $author_id

    public function comments()
    {
        return $this->hasMany(Comment::class);
    }
}


class Comment extends Model
{
    // @property int $id
    // @property int $post_id
    // @property int $user_id (author ids + guests ids)
    // @property string $content

    public function post()
    {
        return $this->belongsTo(Post::class);
    }
}

Post can have author and guests comments so user_id field in comments table can contain author_id and guest_ids.
| id | post_id | user_id | content |
| — | ——- | ——- | ————– |
| 1 | 1 | 1 | author comment |
| 2 | 1 | 2 | guest1 comment |
| 3 | 1 | 1 | author comment |
| 4 | 1 | 3 | guest2 comment |
| 5 | 1 | 2 | guest1 comment |

I need to get posts list with eager loaded comments count for author and for guests, so my question is:

How can I get the count of author comments (author_comments_count = 2) and the count of guests comments (guests_comments_count = 3) using withCount()

Thank you in advance