Add rows together depending on another row/column value

Hi Camargo

Thanks for you're help. I will try my best.

Below is a snippet from the  table (excel) I am working from. This table contains a lot of ledger codes with various numbers but I need to get the total sum from adding together the 'actuals from period' column but from a selection defined by specific Ledger codes within the table and then take that as a percentage from another figure. The other figure I have calculated in a measure so I guess I can just add that to some Dax code but where I am struggling is to get the total from a selection from the 'actuals to period' column defined by/filtered by specific ledger codes.

I could do this in Excel and maybe I need to do this and then import it into PBI but it would be great to not have to.

I have tried creating various measures but I'm getting nowhere and part of me thinks I need to go about it another way but I'm not sure how. Any help would be greatly appreciated.