Directory route.tsx that hides when visiting child route?

I'm attempting to do a mixed directory and flat structure but I can't see a clear way to have a route.tsx file (being the directory path) and having the ability to make non-nested routes. For example I would like route.tsx to be visible in the background of my /invite routes which render a modal but I would like the route.tsx to not be rendered when visiting /$userId. No matter what I do it seems route.tsx will render and if I change it to index.tsx then I don't get the content in the background for the modal.