I would like to a custom aggregation that either doesn't use geohash'ing or uses geohash as a sub-aggregation.
Imagine you are mapping schools or fast food restaurants. I'd like to aggregate by the school type (elementary, middle school, etc.) or restaurant chain name first, then map the metric of count, average, etc. In this case geohash, as a sub aggregation, is fine. (Basically, I have some term/identifier I'd like to use as first level aggregation.)
But I would also like to show the first or last school/restaurant opening, in which case I'd like a top_hits sub-aggregation and not use the geohash (or, in some cases use top_hits with the geohash).
Is there any way to do this? Should I open a feature request issue on GitHub?