I'm trying to build a workaround to this idea: https://community.esri.com/t5/arcgis-survey123-ideas/appearance-option-to-view-repeats-stacked-in/idi-p/947271 - i.e. viewing a summary of repeats in tabular format. I actually want questions in my repeat to update based on how the user edits data in the summary grid, instead of having to scroll through each repeat to do this. For example, updating plant heights once all plants have been collected.
To do this I want a question within my repeat to reference some extra questions I've created, based on the repeat number. So, for repeat number 1, I want to bring in the value from '${species_height_1}' - which sits outside the repeat. If I hardcode this, it works, but if I try to build a string to reference this i.e.:
concat("${species_height_", position(..), "}"), Survey123 seems to read it literally and I get this error:

Any ideas how to make this work? I can build a workaround to this using a long-winded if statement (ideally we want to have up to ~50 species available...), or using a javascript function, but I feel like this is a cleaner and faster solution.
Cheers