Sorting feasability?

This is possible with leaflet-optiongroup and leaflet-featuregroup.

Thanks.

Do you have any experience or advice for generating the geojson file from within wordpress?

I have the data for a set of markers in the wordpress database (used in other parts of the site), how could I automatically produce a geojson file that extracts from this database?

I would use https://overpass-turbo.eu/ for the boundaries. These you can export to geojson. Or get the ids for the administrative areas from https://www.openstreetmap.org and then use https://polygons.openstreetmap.fr/ to get the geojsons. Load the geojsons with leaflet-geojson color=... src=...]Name[/leaflet-geojson] Then use

[leaflet-optiongroup option="color" values="blue, red" groups="Diocese Boundary, District  Boundary" visible=0,1]

It is easy to generate the markers from a database. Do you know php?

Can I help you further? Otherwise I will set the thread as resolved.

I have made it all work now thank you very much for pointing me in the right direction.