Thanks Nathan!

I figured out a way to gather the first value from a collection using jQuery.  In the example below, both the collection and css class are named User_Information.  I assign events to the User_Information collection so that whenever a Last, First name is entered, the first last name is retrieved and assigned to the Request_ID_Suffix field.  I could not determine a good way to trigger (or hook into) the collections delete event, hence the generic click event.

// Set the request ID suffix
function setRequestIDSuffix() {
  var idSuffix = $('.Last_First input').first().val().split(' ', 1)[0].replace(',', '').trim().toUpperCase();
  var requestIDSuffix = $('.Request_ID_Suffix input');
  requestIDSuffix.val(idSuffix);
  requestIDSuffix.text(idSuffix);
  requestIDSuffix.change();
}

var userInformation= $('.User_Information');
userInformation.on('change', '.Last_First input', setRequestIDSuffix);
userInformation.on('blur', '.Last_First input', setRequestIDSuffix);
userInformation.on('click', setRequestIDSuffix);