Guess we're refining oil now. At first I just had a mixed output and tried to sort it with a splitter, satisfactory style, but I guess you can't set a filter like that. From what I could tell the only option there was to prioritize one type of input on a certain output, but not set A-> and B <-. But then I discovered you can sort on the inserter type item to begin with, which finally explains why they're named sorters and not inserters. (Also: I'm still getting used to the fact that each building has a hole that absolutely looks like a belt port, that is actually the sorter connection.) That and the pressing the function keys on my keyboard to place stuff. Odd ass keybinds.