Instead of tinkering with the AEM platform, you can as a test, try tinkering with the basePage template. Within your basePage template, you can add HTML and CSS like so:
<sly data-sly-test="${wcmmode.edit}">
<style text="text/css">
.extra-author-buttons { position: absolute; top: 50px; left; 50px; background-color: red; }
</script>
<div class="extra-author-buttons">
<a href="${currentPage.path + '?groupName=groupone'">View Group One</a>
<a href="${currentPage.path + '?groupName=grouptwo'">View Group Two</a>
</div>
</sly>
Hope this helps.