If they are closely confined then I would seperate them - they do peck chicks that are not their own.
They also get surprising aggressive towards all other moving objects when they've got young chicks.
We've got two girls who have harmonised their breeding cycles, and they always nest right next to each other and are no problem until they start to take their chicks out from the nest, then it's endless fighting and chick swapping and pecking.
This last time we seperated them into two different coops and it solved the problem for a little while, now at a week old they are free ranging and the two girls always have to be in the same place at the same time, and they want to sleep in the same place and they keep fighting constantly and the chicks have no idea who their mother is, sometimes one has five chicks, sometimes one has four, other times there's nine chicks following one girl and the other is away 'partying' with the rest of the flock.
They manage OK, but if you can seperate them until they know their own chicks and the chicks know their own mum, I think it'd be better. With only five eggs between them, you might be better choosing one to be the mum and move her and all the eggs to different place, the ex-mum-to-be will soon start laying again.