SEO of several Companies / Contact for several Accounts


maybe i dont understand the structure good enough. So i am happy for any hint:

A Lead turns out to be the SEO of several Companies. I convert his Lead into an Account (and a Contact is created for him automaticly). I create now the other Companies (Accounts). How do i assign the Contact to the other Accounts? Or do i need to have for example 8 Duplicates of the Contact?

Thank you for your help!