For synchronizing multiple tasks on a single device, even at different rates and on different subsystems, you do not need to synchronize any clocks. Because the device derives those clocks from the same internal oscillator, you need to share only the Start Trigger among the tasks so the clocks start at the same time.
To perform Start Trigger synchronization, configure start triggering on all slave tasks, setting the trigger source to the internal Start Trigger terminal from the master task, such as ai/StartTrigger. You do not have to configure start triggering on the master task. All tasks include an implicit Start Trigger, which occurs immediately when the task starts.