Regardless of the causation, I would expect any group to dwindle as each member passed the area or approach to his home area.

At the same time, one might also expect some of the core group to stay together with the persons experienced with the area.

Example, In Oklahoma or Texas, I would be comfortable with my surroundings. If out on the rivers mentioned up this thread, I would be sticking with someone with the knowledge of said rivers and traveling on them. Tis all unique, and one hell of a long walk.