Posted this question elsewhere and got a great answer:

https://learn.microsoft.com/en-us/answers/questions/1153653/parsing-xml-data-into-multiple-datasets.html#comment-1154683

     SELECT
       ROW_NUMBER()OVER(ORDER BY Caseid.value('@caseid[1]', 'int')) AS...

Hi Jonathan AC Roberts,

Thanks for your input.  Your LEAD/LAG CTE Solution was pretty much exactly what I wanted.

Thanks