nameRepeater

detailsRepeater

Note that this repeater also has the 'name' column, but it's not displayed. The name column is used to "link" the two repeaters.

The rectangle displaying the name has a gray selected style, and the rectangle belongs to a selection group called 'hitters'. Note that in order for selection to be unique across rows, you must turn off the repeater's 'Isolate selection groups'

When the nameDisplay rectangle is selected, it filters the second repeater to show only the rows based on that name, using the 'name' column in detailsRepeater

When the name rectangle is clicked, it gets selected. This triggers OnSelected above

When OnItemLoad is triggered, the first row's nameDisplay rectangle is selected (see the second IF). This triggers OnSelected above, which will display the correct columns in detailsRepeater.