Group dates by weekdays

[etaver87]

Hi everyone,

In the attached Excel I would like to group the dates by week. For example it should merge the cells from 23.5. - 27.5. and 30.5. - 3.6. (and so on) and at the same time sum the values of the cell for that week together. So for the week of 23.5. - 27.5. on row 8 excel would show a value of 100 in the merged cell.

Is there an efficient way to make this happen for the whole sheet?

Many thanks for your help!!