You can achieve the desired effect by re-templating the Scatter series type -- you will also need to create custom ScatterSeriesDefinition / ScatterPoint pair in order to accommodate the necessary coordinate calculations for the additional visual elements that will be added to the template.
We have attached a sample application to get you started.
the Telerik team
Registration for Q1 2011 What’s New Webinar Week is now open. Mark your calendar for the week starting March 21st and book your seat
for a walk through all the exciting stuff we ship with the new release!