[jQuery] Applying nextUntil only to h4 containing a link

[jerpod]

I'm using nextUntil to apply show/hide content functionality based on
its "section",  defined as having an h4 heading. This works great.
Thanks, Richard D. Worth, for pointing me to the nextUntil samples)

$.fn.nextUntil = function(expr) {
    var match = [];
    if ( expr.jquery )
      expr = expr[0];
    // We need to figure out which elements to push onto the array
    this.each(function(){
        // Traverse through the sibling nodes
        for( var i = this.nextSibling; i; i = i.nextSibling ) {
            // Make sure that we're only dealing with elements
            if ( i.nodeType != 1 ) continue;

            // If we find a match then we need to stop
            if ( expr.nodeType ) {
                if ( i == expr ) break;
            } else if ( jQuery.multiFilter( expr, [i] ).length )
break;

            // Otherwise, add it on to the stack
            match.push( i );
        }
    });
    return this.pushStack( match, arguments );
};

$(document).ready(function(){
        $("#PageTemplateForm h4").each(function(){
        $(this).nextUntil("h4, h3").wrap("<div class='expand'></div>");
        $(".expand").hide();
        $(".closed").click(function(event){
                $(this).parent().next().toggle();
                $(this).toggleClass("open");
                return false;
                });

        })

I now find I have some h4s that will not have toggling links and
should not have this toggling functionality applied.  The rule would
be that an h4 that contains a link should have its following content
wrapped (up to the next h3 or h4) and hidden.  An h4 that does not
contain a link should be skipped.  I tried:

$("#PageTemplateForm h4 a").each(function(){

I can see why that wouldn't work, because the "expand" div would would
likely be inserted in the wrong place.  How would I distinguish
between h4s followed by links vs h4s not followed by links?  Thanks in
advance!

jp