Can I combine animation of different objects

Hi,

Today I came up with a question. I'm novice in Unity so I think I made a terrible mistake. But I want to ensure that it's a mistake and not my unknowledge. So I have the main FPS Controllet. Inside it, as a child, a CamHolder object. Inside it the Main camera. And inside the main camera an object called "Hands". The Hands object has two child object "left arm" and right "arm". So My Hieranchy is looking like that. : click for the image.

Now I have a walking animation, and an Idle one. These two are in the CamHolder Object. I wrote a script to check when to play each. But now I animated the two hands. The Left one and the rightone in separate files. But for animation I select the "Cam Holder" object. I don't know if that will affect my question. I want to combine all. In particular I want when I hit the walk or run buttons to play the walk animation and if int that state I hit left mouse button to play the left arm animation or the right one if I hit the apropriate right mouse. Even if I hit two if them when the other animation is playing.

To understand what I do, think the Skyrim game when we are in Mage FPS camera. Just like you hit the buttons and the animations is playing that's exactly what I want.

Can I do that? How? I tried tutorials in Animator but I don't have an object. I have 3 different objects. See the image next : click :