Totally agree with Bob.
10 is a big group, and especially with mixed experience, you can almost guarantee someone in that group will have some type of trouble, AMS or otherwise, as you learned elsewhere.
I have had absolutely reliable people in groups who have made inexplicable errors of various types. Staying together reduces the risks.
When going solo, or offtrail, or out of this country, I rent a sat phone. Works well up high, in the open, and even sometimes unexpectedly in low areas. In canyons or up against walls, you might not have satellite in view to get reception. Have I had dead spots in reception in the Sierra? Plenty of times. Only choice then is to move to a clear area, or wait for a satellite to re-position. They are low earth systems, so they do move around and 20 minutes can make a big difference. Taken to ludicrous extreme, for your group of 10, you would rent 10. No one would do that.
