JS: restart loop with a updated index number

Is there a possibility to restart this loop with a new index number:

    let ar = [1, 1, 2, 1, 2, 1, 3, 2, 3, 1];
    let sortedArray = ar.sort();

    let sameNumbersArray = [];
    let numberOfSameNumbers = 0;

    let lastIndexNumber = 0;

    for (i = lastIndexNumber; i < sortedArray.length; i++) {
      if (sortedArray[i] == sortedArray[i + 1]) {
        const sameNumber = sortedArray[i];
        sameNumbersArray.push(sameNumber);
      } else {
        break;
      }

      let lastIndexFromNumberArray = [];
      lastIndexFromNumberArray.push(sameNumbersArray.length);
      lastIndexFromNumberArray.push(3);
      lastIndexFromNumberArray.push(2);


      lastIndexNumber = lastIndexFromNumberArray.reduce(function (a, b) {
        return a + b;
      }, 0);

So basically that the loop (lastIndexNumber) starts with index[0], but then restarts with index[5] and index[7].

How would one add this extra loop?