The question on one or more of the FileMaker forums was asked and answered. Q: How do you get the Count() of the related records in a filtered portal? A: (paraphrased) duplicate the filtered portal and make it one row in height. Place the related summary field, “Count of…”, in the single row filtered portal. Voila! your count is now filter-specific. (The instructions for creating the filter for a portal and summary field are below.)
This recent topic led me to consider what other aggregate fields could be used with the filtered portal. And what about that Go To Related Record script step? Does it only show the related FILTERED records or all related records? The demo (bvoth_aggregates_in_portals.fmp12) and article have been created to answer these questions.
I started using filtered portals in cross-tab reports shortly after they were introduced. These are generally ways to show something very specific in each portal with sorts and filters and usually one row only. I had not explored the use of aggregates in these cross-tab reports until now.
Kudos to those before me that may have discovered these answers and tricks, too.