They will dominate wherever they go, especially if they are not neutered. I regularly see a GS at the dog park, truly the alpha to any and all dogs there, whether they like it or not. I used to take two dogs there, but one, lovely boy, has moved further away, so we go to a different park. The GS would put that lovely boy under the bench every day, bullying him. GS is almost 5 and has never been neutered, nor will he be because his owner doesn't believe in it. I finally realized that if I stand up, say something like Raaah! and put my arms out to seem bigger, he would go away and leave lovely boy alone. Problem was that the other dog I took was the alpha-beta and came barking at me, telling me not to do that to her alpha!