We have a scenario where we want to use the derived properties based on the actual number of tagged records available with one aggregated record. Currently, the derived properties are dynamic and is derived based on the number of records that matches the search term or navigation criteria.
But we want the derived properties based on the actual number of records present in the index per aggregated record.
If you just want something like a static (non-dynamic) minimum and maximum price (for example), I'd recommend calculating it upstream of Endeca as part of your data extract process and tagging it to each Endeca record. Derived Properties are meant to be dynamic, there is no way to derive them from a record set other than the current results (so you would have to do a second Endeca call, and this is obviously not a good idea).