you need to write a function to update the src of the iframe, and add this function as click event handler to anchors. And sent the specific link as the parameter into the function in each anchor. For detail, please look below sample:
<a href="#scrollhere" onclick="loadOnFrame ('/hello.html')">link 01</a>
<a href="#scrollhere" onclick="loadOnFrame ('/world.html')">link 02</a>
<div id="scrollhere">
<iframe src=""></iframe>
</div>
<script>
var loadOnFrame = function(url) {
$("#scrollhere iframe").attr("src", url);
};
</script>