Excel formula - Get the sum of each variable every 6 days

I have the following dataset where I want to get the sum of each variable every 6 days. I can get the total sum of every 6 days using

=SUM(OFFSET($A$2,,(COLUMNS($A$5:A5)-1)*6,,6))

And I can get the total sum of each variable using

=SUMIF(A1:S1,A1,A2:S2)

But I cant get the total sum of each variable within the block of 6 days. It won't increment when I drag the formula. So the results should be

      First batch      Second batch         Third batch
A      B       C      A      B       C      A      B       C
2      2       2      4      4       4      6      6       6