3dsmax – How to export animations to multiple independent fbx with export options in 3ds max

I have a .max model and it contain multiple animations.

I wanna export animations with one fbx file per animation.

The file name of animation must be model@animation.fbx and the name of the clip showed inside the Unity3D must be animation.

How do I export them?

Example:

I have a human model, and 3 animations clips: idle, walk and attack.

1. Idle animation (keyframe 0 ~ 30)
2. walk animation (keyframe 30 ~ 70)
3. attack animation (keyframe 70 ~ 120)

How do I export following files:

1. human.fbx (fbx with model without animation)
2. human@attack.fbx (fbx with animation attack without model) (keyframe 0 ~ 50)
3. human@walk.fbx (fbx with animation walk without model) (keyframe 0 ~ 40)
4. human@idle.fbx (fbx with animation idle without model) (keyframe 0 ~ 30)

(the beginning keyframe of exported files must be 0)

I tried the export selection, but it can’t export multiple animations and its beginning keyframe of the the exported files will be the same as original animation clips.

ex. If I output the attack animation its keyframe is 70 ~ 120, the result of the exported file keyframe is the same as 70 ~ 120. But I want 0 ~ 50.