Event delegation on non nested elements

I’m using Bootstrap group radio button on which I would like to write event delegation.

<div class="btn-group" role="group" aria-label="Basic radio toggle button group">
  <input type="radio" class="btn-check" name="btnradio" id="btnradio1" autocomplete="off" checked>
  <label class="btn btn-outline-primary" for="btnradio1">Radio 1</label>

  <input type="radio" class="btn-check" name="btnradio" id="btnradio2" autocomplete="off">
  <label class="btn btn-outline-primary" for="btnradio2">Radio 2</label>

  <input type="radio" class="btn-check" name="btnradio" id="btnradio3" autocomplete="off">
  <label class="btn btn-outline-primary" for="btnradio3">Radio 3</label>
</div>

Since the labels are not nested in the button, the following is not returning the inputs.

event.target.closest('.btn-check');

Is there a proper way to write event delegation on this type of non-nested elements?