Makro for merging cells/summing

[Dmrs92]

Hello,
I would like to have makro which will be merging cells based on values on next column plus making sum of this cells in column C

So I have:

blank A 5
blank B 4
blank C 6
blank D 7
blank E 9
blank F 11

So excel merge cells where blanks are for A,B,C plus merging D and E and merging F and G so on. Additionally make sum from third column for every merged cell and divide it by concrete number for example 571. Any ideas for it ?


Thank you in advance,