one way to do it would be to use two helper columns (or rows)besides the data
in one enter a designator for each group of four (1,1,1,1,2,2,2,2... 9,9,9,9)
in the other enter =rand() and copy down the column
select all three columns and user <data><sort) first be designator and
second be the rand column
each time you sort you will get a different combination of the top in each
designated set.