Bill, there is VERY good chance that you will still be in the same flight. Being that close (even if you are trending at 5.7), you might as well “request” to play together. Being only a difference of .4, you won’t even notice the strokes. This will ensure that you are riding together every day.
The only problem will be that “slight” chance of the flights being separated right around 5.8-6.0. Worst case scenario is if your 5.7 is at the top of your flight (i.e. 4.6-5.7 index) and that flight happens to be Flight #4. At 6.1 your buddy would end up in Flight #5 (which would be a different rotation altogether)
As i mentioned, it’s very likely that your indexes will be in the same flight (or even at the same courses for that matter) but not guaranteed. But by requesting to “play together” it will eliminate all those small outside chances.