Valve Index Controller fingers


a while ago i started working with the valve index controllers and struggle to find out how to get the curl of the individual fingers. Im currently controlling my hand animations in a state machine, but the only inputs i can acces is the general grip state of the overall hand, e.g. when grabbing an object, but not the fingers seperately.
Is there something im missing in my inputs setup, or how can i access the curl state of the individual fingers?

Best regards and thanks in advance.