Hey dev100000,
You’re right that this is probably beyond the scope of the blueprint functions at the moment. Although it should be possible in code. You can access joints for a skeletal mesh through USkeletalMeshComponent::FindConstraintInstance providing the name of a constraint, or access joint array USkeletalMeshComponent::Constraints directly. Within FConstraintInstance there’s a bunch of methods for setting/updating the limits, drives and positions for the joint.
Hope that helps!
Benn.