This is the result I want:

https://aglaia.es/post-sitemap.xml
https://aglaia.es/page-sitemap.xml
https://aglaia.es/dt_portfolio-sitemap.xml   
https://aglaia.es/lshowcase-categories-sitemap.xml   

I tried doing different sitemaps each on different route on the app directory, like:

route1/sitemap.ts
route2/sitemap.ts

But the thing is this are different routes. I just wan't to be able to go to /sitemap.xml and then get:

/main-sitemap.xml
/secondary-sitemap.xml