Is there a way to updateOptions on a certain mask?

[TechOverflow]

I have two phone number inputs on one page:

<input type="tel" class="form-control maskedPhone" id="telephonenumber_0" name="telephonenumber_0" placeholder=" " value="" pattern="[0-9\s\+]{16}" required="">

<input type="tel" class="form-control maskedPhone" id="telephonenumber_1" name="telephonenumber_1" placeholder=" " value="" pattern="[0-9\s\+]{16}" required="">

The mask should change based on the country selects that are closest to them.

function maskNumberFields() {

    console.log('maskNumberFields')

    var numCodes = document.querySelectorAll("[id^='countrycode_']").length

    for (let i = 0; i <= numCodes; i++) { 

        var countrycode = $('#countrycode_'+i).find(':selected').val()

        if (countrycode != '') {

            switch (countrycode) {
                case 'us':
                    phoneMask = IMask(
                        document.getElementById('telephonenumber_'+i), {
                            mask: '+{1} (000) 000 0000',
                            lazy: true
                        }
                    )
                    break;
                case 'ca':
                    phoneMask = IMask(
                        document.getElementById('telephonenumber_'+i), {
                            mask: '+{63} 000 000 0000',
                            lazy: true
                        }
                    )
                    break;
            }

        }

    }

}

This works fine on all inputs, but updating the phone masks individually is a mystery.

$('#addressbook').on('change', '[id^=countrycode_]', function() {

    var sel = $(this).val()
    maskNumberFieldsUpdate(sel, $(this).attr('id'))
    console.log('this: '+$(this).attr('id'))

})

function maskNumberFieldsUpdate(countrycode, elem) {

    console.log('maskNumberFields update')

    switch (countrycode) {
        case 'us':
            phoneMask.updateOptions({
                mask: '+{1} (000) 000 0000',
            })
            break;
        case 'aus':
            phoneMask.updateOptions({
                mask: '+{63} 000 000 0000',
            })
            break;
    }

}

The mask update only works on the highest i, so my guess is that the the update only applies to the latest phoneMask, but in that case, how would I apply the mask to individual inputs while also allowing them to be updated individually (by element)?