I believe that you could in theory you can set the filter that is used on the page as in this example(Filter) to filter all 4 of the Vizzes at once. Given they all have a value in common between them to filter on.
Below is the code for the stand alone filter per the link above:
<body onload="initViz();"> <div id="vizContainer" style="width:800px; height:700px;"></div> <div id="controls" style="padding:20px;"> Year: <select id="changeYear" onchange="yearFilter(value);"> <option value="">All</option> <option value="2013">2013</option> <option value="2014">2014</option> </select> </div> </body>
Reusing the "yearFilter" function in each of the embed codes I believe will allow them all to be refreshed by the single filter change.
Hope this helps!