Importing mechanical animation from 3ds max to UE4

hi, i need help with 3ds max to UE4 animation import process. So i have an animation in 3ds max already done, it’s about construction process of a bridge system, basically it’s a scene of a crawler crane picking a bridge segments and placing them in some places. The crawler crane’s rig are very simple, i mainly use link and constraint feature in max, i only use bone for the stretchable sling/cables. Now i want to try to use UE4 for playing this animation in realtime 3D. I have tried using Unreal Studio’s datasmith to bridge between max and ue4, but i just realized that it can’t export any constraint and bones system from max. In UE4, i have the objects imported properly via datasmith, and i have an animation sequence where i can play the imported animation. Now, the bridge segments movement are fine, the rotation and movement of the crawler crane are okay, but the constrained and stretching sling/cable animation is not working. i connected them in max using lookup constraint, stretchable bone etc.
I need to know how to properly prepare this kind of scene in max and how to bring all the animation into UE4. Do you have a solution for this case?

This is the animation