How to obtain an ordered list of coredata managed objects via accessing them via a relationship?

That is:

* have the following entities: LIST, LIST\_ITEM (includes an 'Order' field), and ITEM.
* assume that I have already fetched the list I want to work with
* I can then use the coredata relationships to get the LIST\_ITEMS via using the relationship: e.g. "list1.listItems", and then for each of these LIST\_ITEMS I can get the ITEM ("listItem1.item")

But if I really just want, from the LIST, an ordered list of ITEMS from the list, based on the "Order" field in the LIST\_ITEM, what is the easiest way of doing this?