Welcome dear brin,
Although I don't know your exact situation, however, I tell you my thoughts.
The fact is that Akita was originally used as a hunting and fighting dog. In particular, Akita was used in bear and boar hunting. Besides, they have been performing services under the samurai.
When the dog fight was banned in Japan, Akita becomes a "social" dog. Nevertheless, he retained much of the original temperament, of course. Consequently, he sometimes can be overbearing toward other dogs.
I don't know if your two dogs are same gender.
If this is so, then this behavior is perfectly understandable. Due to the Akita's hunting instinct, you need it to use to other pets. However, if that use happens, Akita has pretty well with them.
Likewise I don't know, if there is a kid in your family. Akita gets along well with children in general, and actions against them protectively. Nevertheless, it doesn't behave as a real playmate of kids.
I suggest you to go to the 'Dog Training and Behaviour' sub forum here. Then push the 'search this forum' button top right. Type your issue into the window then push enter. You'll find anwers to your problem there.
Many successes,
Alex