xsl expand and collapse after "N" child elements

I have XML that can has variable number of child elements.

We need a way to add a expand / collapse feature when there are more than "N" number of child elements.

Example XML

<?xml version="1.0"?>
<TestXML>
    <N>Test</N>
    <NTList>
        <NT>
            <NT1>NT1 Test 1</NT1>
            <NT2>NT2 Test 1</NT2>
        </NT>
        <NT>
            <NT1>NT1 Test 2</NT1>
            <NT2>NT2 Test 2</NT2>
        </NT>
        <NT>
            <NT1>NT1 Test 3</NT1>
            <NT2>NT2 Test 3</NT2>
        </NT>
    </NTList>
</TestXML>

So in this example we would like to add the expand / collapse if there are more than 2 "NT" inside the "NTList".



I think this is close but I can't find a way to determine when to add the expand / collapse after "N" records has been reached.



Something very basic like this for the HTML output:

N : Test
NTLIST
    NT (1)
        NT1 : NT1 Test 1
        NT2 : NT2 Test 1
    NT (2)
        NT1 : NT1 Test 2
        NT2 : NT2 Test 2
    NT (+More) <- where this is the link to click to expand the 3rd NT.