Hi Mark,
Thanks for your reply. I did try the radioGroup button with validator. I also tried the sample xpage that you suggested in the previous post and it is working mine. Below is the xpage that i was trying on and it is still not working for some reason. Can you please help me identify whats wrong in it. 
 
xPage Sample: 
 <?xml version="1.0" encoding="UTF-8"?>
<xp:view xmlns:xp="
http://www.ibm.com/xsp/core" >
 <xp:radioGroup id="radioGroup1" required="true">
  <xp:this.validators>
   <xp:validateRequired message="Select it"></xp:validateRequired>
  </xp:this.validators>
  <xp:selectItem itemLabel="1" itemValue="1"></xp:selectItem>
  <xp:selectItem itemLabel="2" itemValue="2"></xp:selectItem>
  <xp:selectItem itemLabel="3" itemValue="3"></xp:selectItem>
 </xp:radioGroup> 
 <xp:button value="Submit" id="button1">
  <xp:eventHandler event="onclick" submit="true"
   refreshMode="complete">
  </xp:eventHandler></xp:button></xp:view>
 
 
Thanks Again. 
Yusuf