Combined sitemap for subfolder and site

Hello. I have a main blog site and a subfolder (site.com/sub-folder) that looks like a regular category for this site, but with more functionality.
I want to make the sitemap merged. As if the subfolder of the site is a category.
In reality, I have two cards. For the site and for the subfolder.
Is it possible to make a general map for the site and its subfolder?