If two people have a chance of, or plan to separate, while hiking, then each needs to pack as a solo backpacker. When my husband and I go, we go as a pair, and always stay within sight of each other while walking. We will go off fishing different directions once in camp. The big issue then is who take the dog? We have a set "come home" time, but do not panic if someone is an hour late. Another friend and I backpack together but pack entirely separate, even cook separately and each of us has a tent. We stick together while walking (she is directionally challenged) but sometimes actually camp about 100 feet from each other. We both like our "space". Regardless of method, it is good to come up with an emergency plan of what each will do IF you get separated or someone "goes missing". If I were going with kids, I would take walkie-talkies and make them check in regularly.