While this should be mostly possible, formulas probably aren’t the solution. Formulas only have access to data within their own row, so they won’t be able to gather up data from other rows to create the week based totals.
Instead, you should be using the scripting block and/or hiring a JavaScript developer if you don’t feel comfortable figuring it out yourself. The script would fire via a button in the blocks menu whenever you want to calculate the totals, ask the user any necessary followup questions (which rows are we working with, for example), then print out the results however you like.
