JavaScriptは同じフォームを別のページに提出する方法です.

<form action="test1.php" method="post" name="form1" id="form1" >
<input type="radio" name="RadioGroup1"  id="radio1" value="1" checked="checked">  test1.php
<input type="radio" name="RadioGroup1"  id="radio2" value="1" >  test2.php
<input type="submit" name="submit" id="submit" value="  " onClick="check()" >
</form>
<script language="javascript">
     function check(){
        if(document.form1.radio1.checked){
        document.form1.action="test1.php";
        }
        else{
        document.form1.action="test2.php";
        }
        document.form1.submit();
    }
</script>