How to use the EachRow functionality from Maatwebsite

Dear Simon,

many thanks for such a great package. I've created an own import class. But I cannot find out how I can use the EachRow functionality of the Maatwebsite Excel package. I want to manipulate the imported class because I need to optionally need to create some belongsTo relationships.

Can you maybe create a small example (if it's even possible) ?

Your sincerely,
Marten