At a time only one date should be selected from three calendars?

 Hi all,
 
I have three Calendar controls on the page and from them user can select the dates
Now Problem is that when user is selecting the Date from First Calendar and then from second calendar  then still selected Date in First Calendar is highlighted how i remove pervious selected date ?
User can only select one date from three calendars?
 
 
 
Best Regards
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