Short answer: don't sweat the small stuff.
Whenever I ride with someone else in any capacity, we always become separated when the terrain is hilly. This is largely because I'm a much better climber than descender. I just let it unfold. I know my own abilities, so I know when and where I have to wait for someone (if at all), and whoever I'm riding with usually figures it out pretty quickly too. It's just a matter of having some trust in your riding partner, and it always seems to work. In fact, this works even when I'm riding with someone I just met at the campsite the previous evening.
There's plenty of time for chatter on the flat stretches, or the point where someone waits for the other person, or even over dinner at the campsite at day's end.
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I am clinically insane. I am proud of it.
That is all.