Is it possible to do _this_ in Jenkins pipeline?

customMatrix.groovy

// TODO: What does call actually return? Is it void?
def call(Closure body) {
    // Call the body of the block and capture it into variables
    Map<String, Object> config = [:]
    body.resolveStrategy = Closure.DELEGATE_FIRST
    body.delegate = config
    body()

    Closure template = (Closure) config.template
    List<List<Object>> matrix = (List<List<Object>>) config.matrix

    template.resolveStrategy = Closure.DELEGATE_FIRST

    for (List<Object> oneRun : matrix) {
        template.delegate = oneRun
        template()
    }
}

Jenkinsfile-fragment.groovy

pipeline {
    // ...
    stages {
        // ...
        customMatrix {
            matrix [name: 'debian',  prettyName: 'Debian'],
                   [name: 'ubuntu',  prettyName: 'Ubuntu'],
                   [name: 'centos',  prettyName: 'CentOS'],
                   [name: 'macos',   prettyName: 'macOS'],
                   [name: 'windows', prettyName: 'Windows']

            template {
                stage("Test on ${prettyName}") {
                    agent {
                        label name
                    }
                    steps {
                        unstash 'compile-artifacts'
                        unstash 'dot-gradle'

                        gradle tasks: 'check', switches: '--stacktrace'
                    }
                    post {
                        always {
                            junit '*/build/test-results/**/*.xml'
                        }
                    }
                }
            }
        }
        // ...
    }
}