Upload & Sell: Off
Well, since a photo I posted is referenced, I feel compelled to respond.
First, I wouldn't use my vintage photo, probably taken by my great uncle, as an example of outdoor lighting. It's a snapshot even though it was captured on a 5x7 glass plate. The lighting isn't horrible, but the regular issues you encounter (eye socket shadows, etc.) are evident. They were on an outing and grabbed a shot. I doubt the photographer thought much past the Kodak "sun over your shoulder" lighting scheme.
Now, here's come advice for Harold. My advice is based on photographing groups outside at weddings and other events. I once had contracts for Senior photos at two local high schools, one which graduated 1,000+ every year. We would have between 300 and 500 Seniors opt for our deluxe sitting, which included outdoor, "environmental" portraits. I had another full time photographer working for me and during late Spring, Summer and early Fall we started shooting @8:00 am and often shot until dark. We had to be able to get good results outside at all times of the day. We also had to work fast.
I suggest you keep your kit as simple as possible. It's hard to use reflectors with groups of 10-15, therefore I suggest a single flash on a stand, high and slightly to the left of the camera. If you are shooting midday, the sun will create an unattractive pattern. Your idea of seeking open shade is going in the right direction. If you are near the woods, getting them at the edge of the woods with an open field in front works well. Use a WhiBal card or other WB device to help correct for foliage cast and/or skylight.
If you do use flash, avoid using too high a setting to prevent the overfilled look.
I suggest you avoid the brute force approach of using multiple flashes. This can create a confused and ugly lighting pattern. The time you spend fiddling with equipment rises exponentially with every light you add. That time is better spent grouping and posing and shooting for good expressions.
Is this a family photo? If not, do you shoot part time? You sound like you're primarily interested in gear and you see this as an opportunity to use a captive audience to fiddle around with stuff. Be aware that more than likely, your subjects aren't nearly as fascinated with the nuts and bolts of photography as you are. If this gathering is solely to capture the photograph, they will give you five or ten minutes to get the image. If this is a sidebar at an event, such as a family reunion or wedding, you'll be lucky to get two minutes of their time.