Hi everyone, if you know what kinds of orders will use third party shipping, you can use an automation rule to charge shipping to a third party account.
The second part of this article goes over how to set that up: https://help.shipstation.com/hc/en-us/articles/205901668
An error occurred while saving the commentJames (Matt) Lloyd UPD Urns commented
I agree with Eddie! I do ALOT of shipping on other customer accounts and it slows down my process to have to pull up the info each time.