I think you will be able to manage it by just being observant. But it is unlikely you will ever get her to bounce around happily with the other dogs, like your other dog does. As long as you make sure that trips to the dog park are alternated with trips to somewhere where your dog can chase the ball and be herself, I think you'll be ok. Though having said that, you may want to think about trying to lessen your dog's ball obsession. I remember reading a blog post a while back by a woman who came to the realisation that her dog's ball obsession caused him lots of anxiety and when she limited the use of the ball and replaced it with other excercise, he was actually a happier dog. Taking your dog bush is a great activity for most for example.