Crush Tools subtotal

Given foo.csv:

group1,1,2
group1,1,3
group1,1,4
group2,1,5
group2,1,6

We want to subtotal columns 2 and 3 (individually) by group in column1:

subtotal --key 1 --sum 2,3 --delim , -i foo.csv

group1,1,2
group1,1,3
group1,1,4
,3,9

group2,1,5
group2,1,6
,2,11