Here is my interpretation of what you are asking. It seems that this woud be very easy in Simulink.
You have signal PT which is available in System A and System B. System B performs some process and provides another signal to System A which is delayed from signal PT.
In Simulink, you would simply add a "transport Delay" block on the Signal going from B to A, assuming that your model is structured as a "continuous time" model. Inside the transport delay block, you simply specify the duration of the delay time.
If the model is a discrete time model, then the "Memory" block can be used to implement a delay. The memory block specifies the number of discrete time samples to delay, so in this case, the magnitude of the delay is limited to an integer multiple of the discrete sample time (i.e. the memory block specifies a delay of 1 sample or 2 samples, etc.)
