Import Action Override The Whole Process

Hi, everyone! I want to create Import action for customers but i need to override the whole import action so it can handle the relationship between customer and company. A customer has an id, team_id and company_id, and the company has all of the important fields like name, identifier and etc. How exactly do i handle the whole process, because the job wants to insert into the customers table. And i really need this to be a job.