Calculate sum with conditions

Hello All
On the attached worksheet I have blocks of data in cols A to E separated by either date,course or time.Values which correspond with the data are in col G.I would like to add the values in col G for each block and place the results in col J in every row of each block as shown.There are some empty cells and zero values in col G .There are around 70000 rows in the worksheet,I have placed empty coloured rows between the blocks for clarity,there are no empty rows in the data.Many thanks for help given.

Please show the desired result in your file.

Blocks are separated by group of time? i.e block 1 time = 405, block 2 time = 440?
If so, try in J2:

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or, in excel2007+

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remove the title heading in Cell J1, then use

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Maybe you can do as I suggested in #3.

So, try this again:

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