Declarative Jenkins pipeline with Nightly deploy for master branch

I wanted to translate some jobs to the new Jenkins 2.0 declarative pipelines. At the moment they are 3 different jobs:

1. CI --> PollSCM every 5 min (only master), build and run tests.
2. NIghtly --> Run every night (build, test, integration test and deploy on nightly server)
3. Sprintly --> It is a parameterized job that runs with manually created tags every Thursday. (build, test, integration test and deploy on sprintly server)

For this purpose, I have a small project in spring with maven that will be the best example for me to start (Simple, easy and fast to be built).

At the moment I have already a Multibranch pipeline for the CI build but I want to integrate into this job a Nightly and Sprintly build.

• Nightly: Run a Cron job on the night over the master branch to be deployed in Nightly Server.
• Sprintly: Be build over a Sprintly_tag generated by me in the master branch to be deployed in Sprintly Server.

At the moment I have this JenkinsFile

pipeline {
agent {
    label 'master'
}
tools {
    maven "Apache Maven 3.3.9"
    jdk "Java JDK 1.8 U102"
}
triggers {
        cron ('H(06-08) 01 * * *')
        pollSCM('H/5 * * * *')
}
stages {
    stage('Build') {
        steps {
            sh 'mvn -f de.foo.project.client/ clean package'
        }
        post {
            always {
                junit allowEmptyResults: true, testResults: '**/target/surefire-reports/*.xml'
                archiveArtifacts allowEmptyArchive: true, artifacts: '**/target/*.war'
            }
        }
    }
    stage('Deploy') {
                sh 'echo "Deploy only master"'
    }
}

It runs every branch when something is pull to Git and also Run around 1 oclock in the night (but still running all the branches).

Any idea or hint to do that? The code to do the deployment is not required I only want to know how to filter/split this branches being in the same JenkinsFile

Many thanks to all!

Edit: I can also use but It will run all the branches in the night (can I made this filter only for the Cron job?)

        stage('DeployBranch') {
        when { branch 'story/RTS-525-task/RTS-962'}
        steps {
            sh 'echo "helloDeploy in the branch"'
        }
    }
    stage('DeployMaster') {
        when { branch 'master'}
        steps {
            sh 'echo "helloDeploy in the master"'
        }
    }