MarketPress: How do I add the "Author" field to the Manage Order page?

I’m setting up a store which will have many collaborators posting products into it, so I need to figure out a way to be able to see the “author” field in the manage order page, so to know which author is generating more sales and pay commission based on these sales.

I undertand that can be accomplished with Multisites, but that’s not an option I’m looking to explore. I just need to add the “author” field to the manage orders pages. Is there any way to accomplish that?