Create an Asana project task from the initial email sent to a mailing list. Emails from your company's domain are ignored. Configure this script to run based on an every minute trigger.

Code.js

function forwardLabelToAsana() {
  var asana_email = 'x+FirstNumber@mail.asana.com';
  var domain = '@company.com';
  var inbound_label = GmailApp.getUserLabelByName('recruiting/recruiting-inbound');
  var destination_label = GmailApp.getUserLabelByName('recruiting');
  var threads = inbound_label.getThreads();
  
  for (var i = 0; i < threads.length; i++) {
    // We only care about the first message in a thread
    var messages = threads[i].getMessages();  
    var msg = messages[0];
    var candidate = msg.getFrom()
    
    // Check if email is from us
    var from_us = candidate.indexOf(domain);
    
    if (from_us == -1.0) {
      Logger.log('creating task for: ' + candidate);
      msg.forward(asana_email, {
        subject: candidate
      });
    }
  }
  
  // Remove `inbound_label` to avoid re-sending emails to Asana
  Logger.log('removing inbound label');
  inbound_label.removeFromThreads(threads);
  
  // Apply `destination_label` to processed threads
  Logger.log('applying destination label');
  destination_label.addToThreads(threads);
}