administraCursos/app/Permission.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Permission extends Model
{
    public $timestamps = false;

    protected $fillable = [
        'user_id',
        'level',
        'division_id'
    ];

    public function division() {
        if ($this->level === 1) {
            return $this->belongsTo(Department::class, 'division_id');
        } else if ($this->level === 2) {
            return $this->belongsTo(Faculty::class, 'division_id');
        }
        return null;
    }
}