Synchronize nodes

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Hi, I've got following situation:

Two sensors nodes are publishing different values on different topics at 1khz:

SensorNode A publishes measured contact force values

SensorNode B publishes measured angles

Further I've got two subscribers for these two publishers:

Subscriber subA

Subscriber subB

Both Subscriber write on the same state-Object (state.force and state.angle)

Method void control(state.force,state.angle) is called in the CallBackRoutine of subB and does some calculations based on the measured force and measured angle. But what happens is that the force-values and angle-values don't match.

Sometimes it like in the Callback-Routine of subA values are written on state.force 5 times without having been read or sometimes in the Callback-Routine of subB state.force is read 5 times though they values couldn't be updated by subA

How can I synchronize the two nodes? I'm coding in C++ but I'm really new to ROS.

Thanks