Question How to apply different animations on one object?

The Image below shows two sets of arms I am trying to animate. The top image shows both sets of arms with their respective animation. How do you go about applying all animations to one pair of arms? I am trying to go from idle arms to holding the gun animation and vis versa. The second image shows what happens when I mix the two. During run time when I hit a button, the arms holding the glock play the idle arms animation you see in the first photo, and the idle arms play the glock holding animation. However as you can see in the second photo it does not actually play the animations correctly. I get some sort of weird position that seems to be a cross of both animations. I have the the animations set up as "Generic". Any feedback is greatly appreciated. Thank you.