Use a sitemap index file to list and organize multiple sitemaps for the same website. This file can contain up to 50,000 sitemaps and should go into the root directory.

A publisher inquires about Google’s stance on having both a news sitemap and a general sitemap on the same website. They also ask if it’s acceptable for both sitemaps to include duplicate URLs.

Google: Sitemap Dates vs Web Page Dates Apr 25, 2019 - 8:26 am 2 — by Barry Schwartz ...