Since you are impoting the data from another file, you could do 6 imports, mapping a different column of this data into the Modules column each time.
Or you can use 6 Replace field contents operations to copy the data over after import.
In both cases, you can do this manually if its a one time fix or you cn create a script if you will need to do this repeatedly.
Ah, found the solution myself, via google:
Create a calculationfield:
Module Intake en diagnostiek & Module Stabilisatie & Module Oplossingen & Module Veranderen & Module Accepteren & Module Onderhouden
This works as long as there are no double entries. I think.