Need to group rows until they reach a total and then group the next batch and so forth

[thekaoboy]

I have a long list of zip codes and a total units within each zip code. I want to create groups of zip codes where the totals add up to a certain number.

In the example table below, the zips and counts are in no particular order. But I want to start adding up the counts cumulatively until they reach the magic number of 43 and then that would represent Group A. Then start the cumulative count over again until the total reaches 43 and then that is Group B. And so forth. The Column marked "43" is a sample of my desired result.

Thanks all.

Zip	Count		43
30526	8		Group A
38212	13		Group A
38430	8		Group A
13476	19		Group B
78768	9		Group B
70158	3		Group B
63321	10		Group B
29800	6		Group C
70909	1		Group C
64779	10		Group C
87976	16		Group C
57904	10		Group C
88979	19		Group D
60494	19		Group D
70390	8		Group E
17882	15		Group E
65415	1		Group E
97033	4		Group E
57637	11		Group E
41411	18		Group F
91239	8		Group F

 

[Joe4]

Here is a way you can do it with a helper column.
Assuming that your data is in columns A and B, and the first row of data is in row 2, place these formulas in the following cells:
C2: =B2
D2: Group A
C3: =IF(C2+B3<=43,C2+B3,B3)
D3: =IF(C2+B3<=43,D2,"Group " & CHAR(CODE(RIGHT(D2,1))+1))

Then copy the formulas in C3:D3 down for all rows.
Note that this will only work up until "Group Z".