After the recent large No SLA x100 race, Inbounds x25 has been renamed to just x25 and now has subcategories for the 4 main categories. 2838 also implemented some more features into his build of SourceSplit to fit these types of of "multi-runs" (big thanks to him here). I've written a guide on how to use/install it HERE.
Also as a sidenote, I did remove x25 Two Instances (where you have the game open twice and can switch between them while one game is in a cutscene) because nobody besides me has run it in the 4 years it's been here, and it's a bit of a pain to set up. It's also just stupid in general.

As always if I've messed up the rules (or in this case the guide) please do feel free to reach out to me.