Suppose you want two entity generators with periods of 1 and 1/3 to create simultaneous entity departures every second, so that event priorities determine which entity arrives at the queue first. By counting events at each value of time and checking when the count is 2, you can confirm that two entity generation events are truly simultaneous.
The model below uses two Event-Based Entity Generator blocks receiving the same input signal. You can see from the plot that simultaneous events occur every second, as desired.
Although this example uses the Instantaneous Event Counting Scope to plot a #d signal, you can alternatively use the Instantaneous Entity Counting Scope to count entities departing from the Path Combiner block.