Ideas and Discussion: What Features Do You Want in openHAB 5.0?

Development Features
451

I would love to see modular sitemaps where we can have fragments of sitemaps in separate files and some way of including those fragments in a sitemap..

This already has been discussed a couple of times:

Include sitemap parts into another sitemap - Setup, Configuration and Use / Items & Sitemaps - openHAB Community

Structure of Sitemaps, Items and rules - Setup, Configuration and Use / Scripts & Rules - openHAB Community