Swift NSSortDescriptor: Sorting alphabetically, start at other letter than "A"

Question

I want to sort alphabetically but starting with another letter than "A". And then wrapping around when the sort reaches "Z". So that means for example starting at "E":

E, F, G, H... Z, A, B, C, D

The normal sort descriptor is

NSSortDescriptor(keyPath: \MyData.dataDetail, ascending: true)

How can I change the sort descriptor to allow for this functionality?