Sorry @J_Knime_Work, I should have read more carefully.
Regarding this:
I have no solution. As far as I know, you can act on the newly created column as an output of the node, not inside it.
I cannot picture your needs clearly, but this is something you could potentially but not necessarily do with loops or with a script in Python, R or Java.
There is a guide made by KNIME called “Fron Alteryx to KNIME”, and at page 23 it says something that can help.
Also, have a look at previous topics on the forum, like this one (confirms what it’s written on the book above):
Hope it helps solving your problem.
Have a nice evening,
Raffaello