IRR on conditional subset of cashflows
 

Hi,

I'm having some trouble calculating the IRR on a conditional cash flow (CF)
series. The situation can be summarized as follows;

Company - characteristic - CF date 1 (eg Q1-yyyy) - CF date 2 - ... - CF
date n
A Blue -10 -5
100
B Red - 8 3
50
.. . .
.. .
.. . .
.. .
.. . .
.. .
Z Blue -5 2
10

Now I would like to calculate the IRR of a summarized cash flow series under
certain conditions, without having to manually calculate a new row of cash
flows. In other words I want something like (fx could I be interested in the
'Blue' companies);

(IRR(sumif($B:$B;"Blue";C:C) : sumif($B:$B;"Blue";N:N) ; 0,1) + 1)^4 - 1,

where 'N' states column/CF date.

Hence I want a range of values that is summed under certain conditions, on
which I can use the IRR formula.

I hope someone can help me.

Thank you in advance