Merging time and date data

Hello,

I hope somebody can help me with this. I've uploaded a sample of my dataset below. The table to the left is the original data, the table to the right shows the way I would like to transform it.

As you can see on column A, date and time measures have been taken every 80 seconds with associated values for columns B to D. I would like to transform my dataset in the following way:

Intead of having date and time measures every 80 seconds, I would like to have them every 240 seconds (4 minutes). That means rows should be merged by three for the whole dataset. As for the values in columns B to D, that would imply summing them every three rows to a single row. I have left the formulas in the cells for the table on the right hand side for better understanding.

Is there a way ro automat this process for a whole dataset with thousands of rows?

Any input is appreciated!