2 y/o Female's aggression toward the ONE dog she needs to like

[wReckingCrew]

My Dad and I tried to introduce our dogs for the first time today at the park across the street. My Asti is 2 y/o, and the sweetest, most well behaved dog (esp GSD) I have ever met. I recently adopted her from a foster family where she lived with two other dogs and two cats. Got along perfectly with all. She has also met other dogs walking and playing at the park. She has been absolutely perfect for me since, gone up north with me to my uncles cabin, gets into no trouble wherever she goes, terrific on a leash or off a leash, I can't explain how good she has been.

My Dad's 8 year old female Golden is the ONE dog I really need her to like as I often babysit her and he will be babysitting for me! I had yet to see an aggressive bone in my girl's body. As we came near each other, she immediately lunged right for my Dad's dog's face trying to bite her. Luckily I pulled away and she moved away just enough that she did not injure her. From that point forward, her teeth were out and she was growling unlike I have ever seen from her.

We will try again in a couple days in a neutral territory in the same way, but I don't imagine what would go differently. Is it possible she simply doesn't like her, and likely never will?