Using field data in a filtered portal row in a calculation field located outside the portal
I am trying to use a value from a field which resides in a filtered portal in a calculation field that resides outside the portal but on the same layout. The filtered portal is a single row summary of totals from a related table that is limited by a designated variable.
What is the simpliest way (preferably without having to run a script) to reference a field value that resides in a filtered portal in a calculation field outside the portal?
If referencing a field value from a portal row is not possible for a calculation, is there a way to reference filtered related data in a formuletic expression that would accomplish the same objective?