Worked for our herd of 2 for 15 years(gelding and mare) with a 2 stall barn where only 1 stall could access the turnout. As long as they were fed separately, all was well and they stood peacefully together in that 1 stall during hot middays or bad rain or snowstorms. Only works if it works with your horses though, they are all individuals. The elderly gelding recently passed on and I am worrying about adding a new horse and how the mare with be.
What can be a major problem is two horses trying to pass through a four foot opening at the same time.
