Most likely at this time of year in the N Hemisphere they´ll become one flock, as Pilgrims have quite a strong flocking instinct. Then, come breeding time, the ganders will stick to the favourite goose most of the time, with the odd excursion to woo one of the other available ones.Hopefully mine will all get along well too! Navine and Miskit (new adults) are already a pair but it'll be interesting how things go next spring! My young male definitely has a favorite of his three, but they're a pretty tight group all told. The arrival of the newbies is at least as exciting as the new barn roof was!
Overwintering together? Do you mean containing them in a smaller space? It´s in the winter that they start to pair off, but depending on the amount of space you have,you may not need to separate them.
It´s 'winter' here now, and they´re all busy sorting themselves out... 5 ganders and their geese. They have plenty of space, so hardly any squabbles.