It sounds like I should refine my question further.

The hiking group has conducted 3-4 day prep hikes every month since July, and will continue to do so until the trip next summer. Standard precautions such as bear-bagging food and filtering water are part of the process on each hike. The group includes Scouters with many years of hiking and scouting experience, who are physically prepared for the trek. Some of the Scouters completed a 2 week hike at the Philmont Scout Ranch 2 years ago. At least 2 Scouters on the trek have completed or will complete Wilderness First Aid training.

The support group consists of other Scouters with similar backgrounds. There are former members of the military, a nurse, a cope (ropes course) instructor, experienced hikers that have completed two prior Philmont trips, and other experienced outdoor types. At least 3 Scouters have completed Wilderness First Aid training.

The purpose of the support group is not to administer IV's or perform the types of high angle rescue that require SAR level training. The '911' button on the SPOT will be used to bring SAR assistance if necessary. But invoking SAR may have financial and other implications, and would only be used in a life-threatening emergency.

The idea is to provide a fallback when the group is too far from the trailhead, or the ranger station to just walk out on their own. The most typical use I see would be to summon transportation for an ill or injured hiker that needs to get off of the trail. However, there are other possibilities, and this post is an attempt to Be Prepared.

I don't see any legal implications in meeting my group part way through their hike to help transport an injured hiker. If a hiker has become stranded and needs a rope/harness to return to the group, I don't think this crosses the line into high angle rescue. Nor am I concerned about being sued for bringing a rope and pully system to aid the group across a traverse in which the existing structure is damaged or unsafe (and there is no other reasonable means of going around). Bringing additional first aid gear to address heat exhaustion, splints for broken or fractured limbs, and a compact purpose-built stretcher to transport an injured hiker seem reasonable.

Prior to SPOT, the standard practice would be to self-rescue for any less-than-life-threatening situation. Any of the items mentioned so far might reasonably be carried on a hike, and used by the group in the normal process of hiking.

Self rescue might including sending a subset of the group with the injured party to a trailhead or ranger station. That would effectively end the hike for those who accompanied the injured party, and might involve several days transport if the group was out in the back country.

The intent here is not to pretend to be SAR, or a triage physician, or a high-angle rescue specialist. The 911 feature covers this. The idea is to provide a reasonably prepared response to a request for help from your group for a situation that is not life threatening.

Thanks for your input.