Retarget Animations from a Humanoid to just Hands

Hello,

I am new to working with animations in Unreal Engine 4. I am trying to create a virtual reality game. One of the resources I am using to help complete this game is this complete project I purchased from the marketplace. It contains a series of animations for a mannequin that I want to use in my virtual reality project.
The dilemma I am facing is that I want to apply the animations from these mannequins to the hands I will use in my virtual reality game. The set of hands I am using for my game are just the hands of the mannequin.
I tried use the retarget process within Unreal Engine. The models match up in terms of their skeletons (or at least the bones in their hands), but the resulting animations don’t look right at all.
Is there a way to retarget these animations? Any help would be appreciated. Thank you.

Best Regards.