You can get different results with multiple broodies like that. As Flockwatcher said, they often work well together to raise the chicks. You’ll see a lot of threads on here where people just love to see how they work together taking care of the chicks. But occasionally bad things happen.
People have reported that one hen occasionally kills the chicks that hatch under another hen.
Sometimes the broodies fight over the eggs or chicks, wanting to take care of them themselves and considering the other broody a threat. Eggs and chicks can get damaged in these fights.
Often hens will go broody at the same time but on separate nests. My one bad experience with multiple broodies came from that. One hen was broody and setting on 15 eggs. A few days before she was due to hatch, another hen went broody on a different nest. When those chicks internal pipped and started chirping, the second broody fought the first broody for control of the eggs. Seven eggs, all with viable chicks in them, were destroyed.
I can’t tell you what will happen with your multiple broodies. They are living animals and unpredictable. As I said, many people have been extremely pleased with how their multiple broodies worked together to hatch and raise the chicks. I wouldn’t try it myself but many people do and are very successful.
You might want to check out this thread on how to break a broody hen. I've always been successful with the raised wire cage method.
https://www.backyardchickens.com/forum/viewtopic.php?pid=2176186#p2176186
Or you might want to physically separate them and give each their own nest and eggs. I’d make sure they could not physically get to each other though, at least until the hens have imprinted on their own chicks. I really like a hen raising the chicks with the flock for many reasons, but in this case I’d be careful.
Isolate a Broody? Thread
https://www.backyardchickens.com/forum/viewtopic.php?id=213218
Good luck whatever you decide. It’s not always an easy choice.