Hello friends,
I have this doubt for a long and i want to share it with you.
In our agency many clients have a PHP template for the home page of their sites, and also have a blog with wordpress as CMS.
When i am optimizing sitemaps, I have two separate files, an index of Sitemaps created with Wordpress SEO by Yoast (which inside has separate Sitemaps tags, categories, posts, pages, authors, etc.) and on the other hand the home page sitemap with the subsections.
As you know the sitemap generated by "Wordpress SEO by Yoast" is dynamic as it creates the sitemap according to current site content, and is updated every time a new entry is raised or modify any URL. This makes it very practical.
I can not have a unique index sitemap sitemaps nesting inside another, as it is not allowed by Google or Sitemap protocol. I read in the Google Support you can upload multiple sitemaps to Search Console but does not say anywhere on upload multiple sitemaps index, or a combination thereof.
In my case, I would have to upload two separately files, the dynamically generated with wordpress and the manual created for the PHP template.
In my opinion there is no problem and Google will index everything properly performing it this way, but I wanted to share it with you to see how you solve this problem and what experiences had.
Thanks and best regards.