BTW, didn’t get a chance to share this earlier: This question (“how do I select an item in a repeating group and then do something with it?” in general terms) is an FAQ, so I made this video exploring this topic:
This is not an exhaustive overview and shows just a few of the things one might do (and, really, only one way of doing them), but you might find it illuminating. Also, leaving this here as more folks need to find this video before asking this question.
Somehow, this seems difficult to find, even though I’ve spammed it everywhere.