Excel macro help needed

[Jaydoubleu]

Hi i have a question regarding excel
Below is my worksheet regarding trades:
Name Amount Type Trade Price Position Capital
0
ABI 1000 Sell -1000 19,89 -1000 19890
ABI 1000 Sell -1000 20,18 -2000 20180
ABI 1000 Buy 1000 20,05 -1000 -20045
ABI 500 Buy 500 19,64 -500 -9820
ABI 500 Buy 500 19,73 0 -9862,5
ABI 1500 Sell -1500 19,65 -1500 29475
ABI 500 Buy 500 19,55 -1000 -9772,5
ABI 1000 Buy 1000 19,55 0 -19550
MT 1500 Sell -1500 19,40 -1500 29103,75
MT 1571 Sell -1571 19,41 -3071 30490,49167
MT 1000 Sell -1000 19,36 -4071 19357,5
MT 1000 Buy 1000 19,35 -3071 -19350
MT 1000 Buy 1000 19,36 -2071 -19362
MT 2071 Buy 2071 19,40 0 -40167,045

These are stocktrades, but i would like to calculate the result of my trades. This i want to do by adding up all "capital" fields for every trade which brings my postition back to 0 (Position field). So in this case the first 5 rows are 1 trade, the next 3 and the next 6. I need a macro which looks at the Cum field and if its zero it adds-up all capital fields belonging to that trade, so all capital field starting at that 0 and upwards until the next Position = 0 is reached (excluding that one ofcourse).
Could anyone help me with such a macro? Unfortunatly im not that gifted that i can do this myself.
Regards,
Jay