I have been searching how to implement clustering groups and subgroups. The case in mind is to cluster based on subregions boundaries (in Brazil, we have, for example, from down to top aggregations, cities, health regions, states, macrorregions...)
So that when zooming out, clustering happens first on cities, then on health regions (grouping several predefined cities) etc...
I see there is a plugin Leaflet.FeatureGroup.SubGroup for leaflet, I checked, a relatively similar unanswered question in Stack Overflow - Leaflet R Package - Cluster markers across multiple layers
I also searched and checked there seems not to be anything in leaflet.extras nor in leaflet.extras2 package directly related to solving this issue.
I started using markerOptions to pass info to JS, within clusterOptions , to customize icons and label info, but haven't been able to implement in JS that desired grouping.
Has anybody dealt with such things in leaflet shiny that could share experience, insights or hints for this?