See Getting Started with OH3: rewriting the tutorial - 6. Model your home with Items & link Channels. The model is based on group membership and Item tags. And it’s way more involved, and subsequently way more powerful than the Group tag on sitemaps.
It would be great if you actually went through the whole Getting Stated tutorial and add comments and make edits as you go. Getting Started with OH3: rewriting the tutorial - 1. Introduction
No, not even for the model which was something supported even in OH 2.5 but was only used by HABot.