could just do a search within the rows in the repeating group

yes - it uses WU and is not ideal but it is simple

otherwise you’d need a unique data for the repeating group that you’d need to update in the backend and then display in the repeating group. this could be triggered from when another data changes it’s data - create/update the aggregate record.

if you need to view the data regularly or export it then you’d need to do the aggregate record method. if the data is viewed infrequently you could cheat and use the search within repeating group method.

the search in repeating group method does a search for each row so every time the row is displayed so it is not the most efficient but it is one way to do it.