Hi @Juergen72,
not quite sure if I can follow where your problem lies.
Could you maybe provide an example on how your input data looks and how the final output should look like?
I think for your supplement data with X you should look at:
For data summary you can look at the GroupBy Node:
For Excel Data loading look at:
For writing the final data to a new Excel check out the Excel Writer:
In general you can try to look in Nodepit or Knimehub for nodes you need (as well as examples using these nodes)
E.g. the basic examples from the KNIME colleagues: Examples — NodePit