Can you post an example of what you'd like to see?
Say I have two tables:
Table A with fields id, toolname_1, toolname_2
Table B with fields id, toolname, toolindex
In a visualization, I would like to use A.toolname_1 and A.toolname_2 as dimensions. I would like those dimensions to be sorted by B.toolindex. My current sort options are by data source order, alphabetically, an aggregation of a field, or a manual static list. None of these 4 is suitable to the requirement. I think I'd like to sort by a field value directly, not its aggregation. Is it possible?
Please let me know if the question is unclear. Thanks!
Your visualization is an expression of aggregate data. if your viz is showing the lowest level of detail then the application of a sort by an aggregated field is moot point.
If a mark on your viz is populated by one record or multiple records with the same toolindex then a min, max or attr will work just fine.
If the marks are made up of records with varying toolindex values then the toolindex field doesn't make any sense in regards to sorting.