Structured data for category pages

We run a wordpress website. Our category pages are a but different from the standard category pages. They are articles in which clusters of underlying articles are presented with some surrounding content. the links to the articles are subcategorized. I understand that "collectionpage" is the right page type and itemlist (OR haspart??) containing the references to the different articles.

My question: should I use separate itemlists for the articles per subcategory or throw all the articles referenced on the categorypage in 1 itemlist?

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