Unpacking ROS messages

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Any suggestions to reduce this repetitive code:

    SendLowROS.motorCmd[FR_0].Kp = msg.Kp[0];
    SendLowROS.motorCmd[FR_1].Kp = msg.Kp[1];
    SendLowROS.motorCmd[FR_2].Kp = msg.Kp[2];

    SendLowROS.motorCmd[FL_0].Kp = msg.Kp[0];
    SendLowROS.motorCmd[FL_1].Kp = msg.Kp[1];
    SendLowROS.motorCmd[FL_2].Kp = msg.Kp[2];

    SendLowROS.motorCmd[RR_0].Kp = msg.Kp[0];
    SendLowROS.motorCmd[RR_1].Kp = msg.Kp[1];
    SendLowROS.motorCmd[RR_2].Kp = msg.Kp[2];

    SendLowROS.motorCmd[RL_0].Kp = msg.Kp[0];
    SendLowROS.motorCmd[RL_1].Kp = msg.Kp[1];
    SendLowROS.motorCmd[RL_2].Kp = msg.Kp[2];

I am trying to use strucutred binding/similar unpacking concepts like std::tie and std::tuple but unfortunatley no success so far.

auto [SendLowROS.motorCmd[FR_0].Kp, SendLowROS.motorCmd[FR_1].Kp, SendLowROS.motorCmd[FR_2].Kp, 
        SendLowROS.motorCmd[FL_0].Kp, SendLowROS.motorCmd[FL_1].Kp, SendLowROS.motorCmd[FL_2].Kp, 
        SendLowROS.motorCmd[RR_0].Kp, SendLowROS.motorCmd[RR_1].Kp, SendLowROS.motorCmd[RR_2].Kp, 
        SendLowROS.motorCmd[RL_0].Kp, SendLowROS.motorCmd[RL_1].Kp, SendLowROS.motorCmd[RL_2].Kp] = msg.Kd;

and another approach

std::tie(SendLowROS.motorCmd[FR_0].Kp, SendLowROS.motorCmd[FR_1].Kp, SendLowROS.motorCmd[FR_2].Kp, 
              SendLowROS.motorCmd[FL_0].Kp, SendLowROS.motorCmd[FL_1].Kp, SendLowROS.motorCmd[FL_2].Kp, 
              SendLowROS.motorCmd[RR_0].Kp, SendLowROS.motorCmd[RR_1].Kp, SendLowROS.motorCmd[RR_2].Kp, 
              SendLowROS.motorCmd[RL_0].Kp, SendLowROS.motorCmd[RL_1].Kp, SendLowROS.motorCmd[RL_2].Kp) = std::tuple(msg.Kd);