FGU still tells me what order they were rolled in because they are separate instances of damage.All four dice where rolled together. Because that's what simultaneous means. Also, because that's the the way it works on a VTT, unless you insist that they are NOT simultaneous.
The thing that is "bleedingly obvious" here is that RAW does not work in this situation.
Look, if you don't want a solution that's fine. Run things at your table how you want. That's the whole point: it isn't certain and this is the GM's job. Just make a call and stop telling people to do it your way.