TO get the same info twice you have to copy it or create a copy.
The easiest way would be to import the data into just artist and title fields and then copy artist to albumartist in 1 go with an action as described in the FAQs:
Anything more fancy like an action of the type "Guess value" that does the duplication and splitting with a single action removes the discrete charme of being able to adapt the import mask with the help of a preview.