Hi, I'm looking to set shipping rules by the customer, I see that there is the ability to do this by the item, is it possible to do it by the customer as well?

Hi. No, it isn't. There has been an enhancement request in since 2012, so please vote: Enhancement #44359 - Summary: Lists > Shipping Items > Include Audience subtab so customers can restrict shipping method based on customer login.

Got it, thank you!