Clocks

I would like to be able to have various actors in game to have different rates at which their Update method is called (to allow actors off screen to update at slower rates for example). This is similar to the way GameWindow has different rates for OnRenderFrame and OnUpdateFrame.

Can someone suggest how to achieve this synchronously? I understand that the best result I can get is an approximation limited by GameWindow's update rate, but not sure how to get the closest result.