=COUNTIF(C36:C36,$G$6) put this in column G and drag down via the square at the corner of the cell.

=IF(G36=1,LEFT(A36,1),"do nothing") put this in column H and drag down as well.

You need to switch on filters at the top of the table, and ensure there are no blank rows in at least one column otherwise filters don't work. The if formula will only highlight the A or B if the number is identified as $ lock the cell reference, when dragging formulas to fill. If the look up value is variable in the table, I would have to reconsider.

You could just do a filter on the existing data to show the rows for the value highlighted without the formulas used.

Not really sure what you want, without really understanding your data. I do a lot of "house keeping" for a spreadsheet normally, with work around set ups before I even get started... Some formulas to think about if you have not used them.