The column filter would be best suited for that task:
After you have done that you could then just reference the result towards your other tables
You could use the dialog oriented
Or write rules of your own with the:
If you have very complicated rules other nodes might also help. You would have to specify the rules.
You can concatenate KNIME tables so that they would then form one table
There is a Pivot node in KNIME - you could then save the results into Excel. Or you could have a pivot table in an Excel sheet and replace the source for the data and then recalculate the results.
There is a node from @AnotherFraudUser (cf. all Excel Utilities) that would allow you to write data into an existing excel file without changing the formats. Although I have not used it much as of yet.
It would allow you to force a recalculation of the values. You could try and see if that would also include an existing Pivot Table in Excel:
And if you would provide us with a minimal example we could further work on that together: