title: Flow agents one by one anylogic
body: <p>I'm simulating a Process in anylogic in which I need my agents to flow from a queue to a Service one by one, and only when the service is empity (namely when the preceding agent has finished with it).
  How can I do? I tried using an Hold between the queue and the service that's true only when the service is empty, and it is ok, but I need the agents to flow one by one and not all together.</p>
  
  <p>Thanks for your help!</p>