add column x values until column y equals

[bleugh]

I'm trying to figure out how to make excel sum the values in column J while column D=0

I've attached an example sheet

basically, if column D = 1 and the below cell D+1 is NOT 0, then it's a unique row, and the value in J is the sum

if column D = 0 then it's a 'duplicate' value, then I need to sum the values until column D = 1 again


i tried to describe it with a simple math formula, but have no luck, see the attached sheet, the 'borders' show the cells being added

been at this for a couple of days now :-(