^ I believe multiple first person view points were used in the story: In The Grove
For those unfamiliar this is one of the stories the Japanese film Rashomon was based off of & if you know that film you can understand how multiple first person povs might work & even add to this story.
Of course when writing first person you have to get the voice down and writing multiple you would have to get several voices down. But I suppose a simple way to establish what character is talking is to name the chapter that. GRRM does this with his 3rd character povs.