We've gotten ourselves into a big of a pickle. We have 7 adult Saxonys - 6 female, 1 drake - and 2 of them are sitting on a single mega-nest of >20 eggs. We believe the other females have been dropping eggs off in the nest every once in a while, but we quickly candled a dozen before Mama chased us off and they were all developing. But before those 2 went broody, we had ordered ducklings. So um... Now we have 7 adults (1 year old) and 17 ducklings (3 weeks old) and possibly more than a dozen hatchlings coming in the next couple weeks. Had I known the girls would go broody, I wouldn't have ordered more ducklings, but here we are. 
I am familiar with introducing shipped ducklings to an established flock. I got all the advice and tips and tricks I could handle on that. But nobody really has any advice on how to go about introducing ducklings to an established flock that also has even younger ducklings. By the time the shipped ducklings are ready to join the adults, the eggs will have hatched.
I planned on introducing the shipped ducklings to the adults over the course of a couple weeks before fully combining the two. But I'm not sure if there should be separation between the hatched ducklings and the adolescent shipped ducklings. I don't think the adult drake will try to kill his hatched ducklings, but I also don't know if I'm creating a weird competitive situation that would make him act abnormally.
We do have the ability to keep all 3 groups separate for a while, but obviously that's not the end goal. We have a duck house with an inside room, an outside screened-in room, an outdoor pen, and then the whole yard is fenced in. I can easily move fence pieces to segregate as necessary, but I have NO CLUE for how long or which group to watch out for.
So if you were in my ridiculous situation, what would you do?

I am familiar with introducing shipped ducklings to an established flock. I got all the advice and tips and tricks I could handle on that. But nobody really has any advice on how to go about introducing ducklings to an established flock that also has even younger ducklings. By the time the shipped ducklings are ready to join the adults, the eggs will have hatched.
I planned on introducing the shipped ducklings to the adults over the course of a couple weeks before fully combining the two. But I'm not sure if there should be separation between the hatched ducklings and the adolescent shipped ducklings. I don't think the adult drake will try to kill his hatched ducklings, but I also don't know if I'm creating a weird competitive situation that would make him act abnormally.
We do have the ability to keep all 3 groups separate for a while, but obviously that's not the end goal. We have a duck house with an inside room, an outside screened-in room, an outdoor pen, and then the whole yard is fenced in. I can easily move fence pieces to segregate as necessary, but I have NO CLUE for how long or which group to watch out for.
So if you were in my ridiculous situation, what would you do?