As per my understanding you have an excel file which contains four columns which corresponds to the four attributes of different entities respectively.
As in the Excel Import Configuration we can have one entity as the main configuration object it will be difficult to manage the association and have a direct import , I can suggest below approach :
1) Create a Processing entity with all the attributes matching the columns required for the import.
2) Create a Custom logic for Import where you will first import in this processing entity and then in the same logic use the imported data and map it in the actual entities.
3) Delete all the imported data in the processing entity .
Maybe you can look into working this out with non-persistable entity but not sure about that entirely.
Hope this helps!
Sunit Kumar Dubey
Thank you very much for your help.
The tip with the Processing Entity has helped me.
I solved the rest with custom Java logic.