Having all girls the same age has many benefits (and drawbacks, of course). The obvious benefits are the purchase of clothing - for the most part Sarah only needs to get one (or two) size. There are no hand-me-downs, which is a drawback, of course.
An advantage of having all girls is that we don't have the competing interests many families have when there are both boys and girls. The girls don't have a brother complaining that he doesn't want to watch a "stupid" princess movie.
The girls DO fight, of course. A day (or sometimes an hour) doesn't pass without Allie, Anna or Emily pouting to Sarah or me that "sissy won't play with me" or "sissy took my dolly" or "sissy hit me". They are siblings. They have their moments.
For the MOST part though, the girls play well with each other. This clip of them playing school is just one example of the MANY creative ways they play together. Barbie is the teacher (I think):