Add every n row meeting a criteria

[ozbeachbum]

Hi Everyone,
I need to add every n row meeting a criteria in another column.
I am currently the following formula to add every n row, but have been unable to work out how to have it only add those cells in the range that meet the criteria in another column.
SUMPRODUCT((MOD(ROW(C4:C20)-4,6)=0)*(C4:C20))
Any assistance would be greatly appreciated.
Cheers,
Dave.

sum n row criteria.xlsx
	B	C	D	E	F	G	H	I
2		1200	I have been using this formula in C2 to add every n row.
3			I need to add every n row where it meets a criteria in column B.
4	CBD	400	EG: Where the criteria is CBD, then the result would be 800.
5		100
6		100
7		100
8		100
9
10	CBl	400
11		100
12		100
13		100
14		100
15
16	CBD	400
17		100
18		100
19		100
20		100
Sheet1

Cell Formulas
Range	Formula
C2	C2	=SUMPRODUCT((MOD(ROW(C4:C20)-4,6)=0)*(C4:C20))
C4,C16,C10	C4	=SUM(C5:C8)

 

[Fluff]

How about

=SUMIFS(C4:C50,B4:B50,"CBD")

 

[ozbeachbum]

How about

=SUMIFS(C4:C50,B4:B50,"CBD")

Thanks so much, do simple.
I'm thinking I needed to still add every n row, but because there is a criteria it only adds those that meet the criteria.
I noticed you show the England Rugby Emblem.
It would be great to see them in Australia again.

 

[Fluff]

Glad to help & thanks for the feedback.

It would be great to see them in Australia again.

Our 2022 summer tour is there (Covid dependant), so hopefully won't be long.