Apply animation to only one hand

Here’s probably a dumb question, but I’ve been looking for hours and can’t find an answer online, or maybe I’m not phrasing it right when I am searching. I am posing a metahuman with the animation rig, and find hands to be a real pain in the butt to pose and make look natural. To save time(ha ha) I downloaded some free hand poses from FAB(essentially one frame animations) but when I try to apply them it screws up my whole pose as it tries to blend the full body of the two together. All I want is for it to affect the hands, nothing else, is there a simple way to somehow tell Unreal to only use the data from the hands and leave everything else alone? I know there are ways to change the weighting of every different bone, but that seems like a whole lot of hassle to go through every time I want to use a hand pose and surely there must be a simpler way. Right? I hope?

Thanks guys and gals, hope to hear from you soon!