Combine Sort

Problem/Motivation

Sometimes it's useful to know which items came from which combine and also be able to sort results with that knowledge. I'd like to see a "Combine sort" that adds a faux field to each select indicating which combine it came from, and then allows sorting by the combine.

Proposed resolution

Create a "Combine Sort" sort plugin that adds fake fields to each select with an Number value. 1 for the parent, and then 2,3,4, etc for the combined views based on their field order.