Description of my core data model:

* Project and Issues entities
* Project has an **ordered one-to-many relationship** to Issues named issues
* Issue has one-to-one relationship with Project named parentProject

Here is my code to obtain issues:

```
let fetchRequest = NSFetchRequest(entityName: "Issue")
    fetchRequest.predicate = NSPredicate(format: "parentProject CONTAINS[cd] %@", argumentArray: [project])
    fetchRequest.sortDescriptors = [NSSortDescriptor(key: "name", ascending: true)]

    let frc = NSFetchedResultsController(
        fetchRequest: fetchRequest,
        managedObjectContext: dataManager.context,
        sectionNameKeyPath: nil,
        cacheName: nil)

    return arc

```

Even though I have all issues from the project object, I prefer to obtain issues using fetched results controller, so they will always be updated and I like the integration with tables. I also like that in navigation controller screen before the projects are displayed using FRC as well.

As you see in the code the Issues are sorted by the name parameter. 

**However I'd like them to be sorted by the order I keep them in the NSMutableOrderedSet of project.**

AFAIK I cannot use NSSortDescriptor with comparator/selector when it's used to Core Data.

Do you know how to do it? Thanks in advance.