Welcome to the world of crate and rotate. You need to keep at least one, and ideally, two, barriers between the mix and Golden inside the house. The situation probably isn't as volatile outside because the Golden has more room to get away from the mix.
I think, from your comments, that the Golden and the mix are both males? If so, there could be a bit of same sex aggression happening, which adds fuel to the "don't get along" fire.
I think, from your comments, that the Golden and the mix are both males? If so, there could be a bit of same sex aggression happening, which adds fuel to the "don't get along" fire.