Drill down Report...Remove the Expand (+) and Collapse (-) button for some groups

Hi....I have implemented a Drill down upto 3 levels. First level is Continents... when a Continent is expanded.... Countries in that Continent are displayed... and when a Country is expanded .... Cities in that Country are displayed.Now, As per requirements ... Drill down option should be given only to some specific countries and not to all.So, is it possible to Remove the Expand (+) and Collapse (-) button only for some Countries??:hehe:Regards,Shree:)