I've had many different experiences with multiple broody hens. I've not felt the need to segregate my broodies when my flock was small. Now that I have a larger flock I have considered it and am prepared for it, but so far I haven't needed to do so. With my last successful broody of shipped chicks, I did segregate mom with babies for a time inside a wired dog crate in the main coop but only while a black snake was attacking the flock. Once I dispatched the snake momma and babies were right back to freedom.
Most of the time when I'd have two broody girls they would be so focused on teaching their chicks that there wasn't much time to intermingle. Each broody would get her bunch to follow her somewhere to scratch and peck. Occasionally the groups would merge but only briefly as the moms would quickly hustle their perspective brood off to safety. Any squabbles would be fast and without fatalities.
I've had single broody girls, co-broody girls (a Silkie and Silkie mix who both hatched and raised two little "farm mix" chicks from my own flock), 3 simultaneous broodies (RIR hatched and raised two White Leghorns, Splash Maran who raised 4 shipped EE girls, and a Partridge Silkie who raised 3 shipped Olive egger chicks). And again, I didn't separate them because they separated themselves.
I did provide multiple chick feeding and watering stations. I attempted to micro manage their environments (force them to hang out or sleep in certain segregated areas) but they wouldn't have it.
Once the Silkie was trying to hatch at the same time as the Silkie mix and they kept fighting over the few eggs each had. So when one would leave the nest the other would go steal her eggs. You may encounter something like that. I ended up labeling the eggs to keep track of who had what. But it didn't matter in the end because as it got closer to hatch I shifted eggs to give both an equal amount to hatch.