Use the Go To Related Record from the parent record to the child records. Then go to the table where you want those records and import them from that Found Set.
Sigh, but using a repeating field for this purpose is not very likely to have been the optimum design choice. Keeping with a related table of records and NOT doing this seems the better approach. There are ways to display such data horizontally without doing this if that is the reason why you want to use a repeating field.