Have you thought about taking a different approach entirely?
When I have multiple elements coming back I often rely on a count of the elements instead of the exact contents of the elements. This helps shield my assertions from small changes in the underlying response while still giving me confidence that the service is still working.
For example I use the following xpath -> count(//errors/error) with an Expect Result of '52'. This way I don't need to change the assertion when the text of an changes.
Maybe it would help if you counted the e-mail addresses instead?
I hope this helps.