title: TeamCity: Prevent 2 builds from running simultaneously
body: <p>I don't want Build Config A and Build Config B to run at the same time. This is because they share the same resource which cannot be accessed simultaneously. However each build config is run by a separate agent so it is possible for them to run simultaneously.</p>
  
  <p>Instead I would like one build config, when triggered, to wait for the other to finish if it is running. For example if Build Config B begins to run but Build Config A is already running, then B would wait until A finishes and then B would run.</p>
  
  <p>I don't think a snapshot dependency will work because that assumes one config has a dependency on the other which is not true in my case.</p>