You are definetly observing the jennies as a grouped up subflock, most likely hatch mates or at least they spent the prior fall together. What is really interesting is how the gobblers won't even mess with them and will leave a group of 10 or more in a heartbeat to search for an adult hen that may be receptive. And likewise, the jennies don't really care about the gobblers socially as long as they have their flock mates around. They will definetly go straight to a gobbler calling if they are separated from their flockmates, however. (not to breed, but just for the social company until they can find their flockmates).
Jennies 'can' successfully nest, but whether they will produce a clutch is primarily determined by their body condition coming into the spring. Early hatched or extremely well fed jennies will lay (usually a month later than adult hens), although their success actually hatching their brood is significantly lower than adult hens. They just don't hide their nests as well and are more susceptible to predation, and for some reason, they will often simply abandon their nests mid incubation. To rely on jennies alone to sustain a population is foolhardy. I simply view the few poults they do successfully raise as 'bonus' poults.
In another 2-3 weeks or so, some of those jennies you are watching will become interested in the gobblers and allow them to mate them (if there are any gobblers left after 6 weeks of hunting pressure)