Skipping indices with a repeater

Question

How do I skip the indices in a repeater such that I can create the following exact string: A • D • G • J • M • P • S • V • Z Is this achievable?

My new code based on suggested answers, I created a function newLetters(index) to determine which letters to print and now my output gives the following string: A •• D •• G •• J •• M •• P •• S •• V •• Z?

import QtQuick 2.15
import QtQuick.Window 2.15
Window {
    id: root
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")

    property string letters: "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

    Rectangle {
        id: control

        anchors.fill: parent
       
    function newLetters(index) {
        if(letters[index] === "A")
            return true
        if(letters[index] === "D")
            return true
        if(letters[index] === "G")
            return true
        if(letters[index] === "J")
            return true
        if(letters[index] === "M")
            return true
        if(letters[index] === "P")
            return true
        if(letters[index] === "S")
            return true
        if(letters[index] === "V")
            return true
        if(letters[index] === "Z")
            return true
    }

        Repeater {
            anchors.fill: parent
            model: 26
            Text {
                text: control.newLetters(index) ? root.letters[index] : " • "
            }
        }
    }
}