Trigger all jobs in a Jenkins organization - https://tomlankhorst.nl/jenkins-trigger-build-organization

trigger.groovy

// https://javadoc.jenkins.io/jenkins/model/Jenkins.html#getItemByFullName-java.lang.String-
def organization = Hudson.instance.getItemByFullName('my_organization')
if (!organization) throw new Exception("No organization by that name")
// https://javadoc.jenkins.io/plugin/cloudbees-folder/com/cloudbees/hudson/plugins/folder/AbstractFolder.html#getItems--
def jobs = organization.getItems()

jobs.each { 
  // find the sub-job that's named "master"
  // https://javadoc.jenkins.io/hudson/model/Item.html#getName--
  master = it.items.find { it.getName() == "master" } 
  // if found, schedule a build with 0 quiet period
  if ( master ) {
    // ttps://javadoc.jenkins.io/plugin/workflow-job/org/jenkinsci/plugins/workflow/job/WorkflowJob.html#scheduleBuild2-int-hudson.model.Action...-
    master.scheduleBuild2(0)
  }
}