Make two more copies of the sub report. Each of the three subs should be sized for one column. They’ll all be identical except each will have a different row filter to show only every third record.
The left most sub will show records 1, 4, 7, 10 , etc…
The center sub will show records 2, 5, 8, 11 , etc…
The right most sub will show records 3, 6, 6, 12 , etc…