I know that Annotations such as Highlights can have tags, which have a global scope in the whole library, and that's great.

But I would also like to be able to divide them in "groups", in the scope of a single document, so that I may organize my highlights by their intended purpose, somewhat similar to Collections in the Library itself.

For example, if I am highlighting text in a document for classification purposes, I'd like to group the Annotations in "Objectives", "Methodology", "Results", and so on. And these groups could have little arrows like Collections to show/hide items inside. This way it would be easier to find personal Annotations in a long document with numerous highlights.

At the same time, this could be used to have groups such as: "General Comments", "Section 1 Comments", "Section 2 Comments", and so on. This way they can be split into sections in a Note for easier exporting, when I "Add Note from Annotations". In a more advanced version of this feature, "Add Note from Annotations" could ask if I want to export all Annotations, or only those in specific groups.

I looked for a plugin capable of doing anything like that but couldn't find any. However, to me, this seems to have enough use cases to perhaps be considered as a built-in feature; perhaps even addressing some reasons for the requests to "merge annotations" (https://forums.zotero.org/discussion/89572/feature-suggestion-merge-annotations).