Observation & species counts per place type within a place

Is there an API call that will give me counts of observations and distinct taxa per place type within a place? I have looked over both the original API and the /v1 API and am not seeing anything that will do this.

I know I can get an enumeration of place ids for a place type in a single API call, e.g. for all of the counties in Pennsylvania:

https://www.inaturalist.org/places.json?per_page=200&ancestor_id=42&place_type=county

But then I fail to see how I could do anything but iteratively call /v1/observations?place_id=# and /v1/observations/species_counts?place_id=# per place_id returned from the first call to get per-county counts of observations and distinct taxa. (Yes, I know place_id takes an Array as input, but that’s no good, as it doesn’t return a breakdown, just one lump sum total for all places.) Even if the 69 counties are broken up into pages of 10, ten seconds is a long time to wait, and will just lead to a lot of user frustration, so I don’t think I do the work for this feature request without some more help from the API to do this efficiently, as I recorded in my comments on the issue here: https://github.com/synrg/dronefly/issues/130

I know I can get these counts per other categories, like per observer, with /v1/observations/observers, or per identifier with /v1/observations/identifiers but place breakdowns seem to have been overlooked. Users are looking for place stats in part to choose locations nearby to visit that might show promise for finding particular things on their hit lists. Is there any way to do it with the current API, or does this need to be made into a feature request for a new API endpoint?