These 2 MediaWiki XML elements carry an attribute named “group”: ref and references. And as you already know, those 2 elements work together.
- https://www.mediawiki.org/wiki/Help:Cite – the reference manual
- https://de.wikipedia.org/wiki/Wotan_Wilke_Möhring – this article has a separate list named “Anmerkungen”, the group attribute calls it “Anm.”
Using this attribute you can easily keep a separate group of references, that does not necessarily provide outside links but e.g. simple notes.