I have a custom "Orders" model with a tree view, and this tree view is frequently grouped by product ID, which is a many-to-one field. I want the average quantity ordered of the group to be displayed in the Group-By header. However, it is currently displaying the sum of quantities ordered, which is not what I want. I am using Odoo Online, so I don't have direct access to the backend. 

I have a feeling this is related to "group_operator," but I don't know of a way to edit that with Odoo Studio. I've tried using the Aggregate option in Odoo Studio, but that just displays the average of every quantity ordered at the bottom of the tree. I'm at a loss for what to try next.