Overriding sort order for a specific autopage

I've got auto-pages set up for categories. 

For some of my categories it makes sense to do oldest-first. 
However, another category is for events, which it makes sense to do newest-first. 

Since they're auto pages, I don't have any front matter to specify. Putting things under the `defaults` key just gives me a heap of warnings. 

I'm guessing this is just completely unsupported? 