Sorry for the late reply, hope this helps anyway...
You can make a js widget within that page that redirects into other sites/pages such as
<script language="JavaScript" type="text/javascript">
<!--
parent.window.location="Your/Link/Here.html";
// -->
</script>
You can insert this onto the page by selecting "insert>html snippet" from the top menu
and if you're linking to one of your other sites, you can use relative linking; but remember, what you have here is in a widget separate from the main html file; so lets say you've got a page under /Site1/mypage.html that contains that widget, you will find that widget in /Site1/mypage files/widget0_markup.html
so, if you want to redirect to, say, /Site2/page2.html, you'll need go back 1 more time than usual, thus,
<script language="JavaScript" type="text/javascript">
<!--
parent.window.location="../../Site2/page2.html";
// -->
</script>
(I might have messed something up and went back one time too little, but you get the idea)