Calculate Discrete Averages, not rolling

On Worksheet 1, I have data in Columns A through Z.

On Worksheet 2, I would like the columns to have the averages of Worksheet 1, however, they can not be rolling averages.

For example, Cell A1, =average(worksheet1!A:C),
then, I want Cell A2, =average(worksheet1!D:F).

Each consecutive cell should calculate the average of the next 3 cells on the other worksheet. Does anyone have a solution of how to do this without having to change the formulas in each cell?

Thanks!

paste this into cell A1, just replace Sheet2 with the proper sheet name and change the 65000 to the number of rows in your table

=AVERAGE(OFFSET(Sheet2!$A$1,0,3*(COLUMN(A1)-1),65000,3))

I tried that formula and it did not work. I am familiar with the offset formula but I don't really understand what this is doing.

Thanks.

please post an example of your worksheet