Those FRS two-way radios are pretty much line-of-site communicators. So if you understand that, they might be useful. But don't be surprised when they don't work.
Bob West is correct about groups splitting up. Very often, the serious accidents are due to a lone hiker splitting off from a group, especially on the descent. It is just plain stupid to hike ahead of the slowest hiker on the way down. It often discourages the sower hiker, which can lead to hiking even slower, and possibly lead to their making bad decisions.
If you are a larger group, it would be best if you all stayed together at least up to Trail Camp. That's pretty much the half-way point. Between there and Trail Crest the radios would work ok, and there are a few places along the crest where they would work.
It is usually around Trail Camp that people begin to suffer from Altitude Sickness, so that would be a good place to evaluate your member's prospects, and make some important decisions about splitting up, etc.
