How to Toggle Sections in a SectionGroup
 

Hey folks,
i want to set two SectionGroups in my Installer. In one of the SectionGroups are two Sections. ONLY ONE Section should be marked. But the whole SectionGroup should be able to unchecked.
Ho can i realize that? I've experimented with RadioButtons, but this seems to be not the answer (When i uncheck the first SectionGroup the second is also deactivated)

Thanks for all your help!
WhoIAm?