Hi there!
I would suggest that you buy your 2 GSD's toys that they can both share. Like chewy ropes or a large tire that they can both tug on. If the male GSD snaps aggressively, take the toy away from him and scold him. Repeat this everytime you catch him dominating the toys. Eventually he'll learn that if he doesn't share the toys, you'll take it from him.
Hope that helps!
