title: Modeling and executing a 1 to n collaboration in BPMN
body: <p><strong>Given</strong></p>
  
  <p>I have the following BPMN process (collaboration), where three actors are involved. Two of them (Actor 1 and Actor 3) represent a <strong>single</strong> instance. While Actor 2 represents <strong>n</strong> instances (open the image in new tab to enlarge).</p>
  
  <p><a href="https://i.stack.imgur.com/BS3uB.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/BS3uB.png" alt="enter image description here"></a></p>
  
  <p><strong>Background</strong></p>
  
  <p>The basic idea is that Actor 1 initiates a task, which should make ALL instances of Actor 2 create data and send it back to Actor 1. In the end Actor 1's activity collect results should collect all the data of all Actor 2 instances.</p>
  
  <p><strong>Question</strong></p>
  
  <p>My question is: Is this even possible and executable to model in one monolithic diagram (while the engine execution manages the instances part), or should I split this into two processes, using signal events? </p>
  
  <p>In the literature, the multi-instance participant (here Actor 2) is usually marked with three vertical lines, but I am not sure, if the engine supports this.</p>
  
  <p>Is there otherwise a better approach to model a 1 to n relation?</p>
  
  <p><strong>Note:</strong> I am still learning BPMN, tell me if I am totally in the wrong here. Thanks a lot.</p>