In order to display the events only in their start date while in the RSEvents! Calendar, some source code modifications will be required. Namely, you will have to edit the file \components\com_rsevents\helpers\calendar.php. Here, around line 313, you will find the following code lines:
for ($i=$start; $i<=$end; $i+=86400)
$this->_event_dates[date('d.m.Y', $i)][$event->IdEvent] = $event->IdEvent;
// Event end date
$this->_event_dates[date('d.m.Y', $event->EventEndDate)][$event->IdEvent] = $event->IdEvent;
which can be either deleted, or commented out, like this:
//for ($i=$start; $i<=$end; $i+=86400)
//$this->_event_dates[date('d.m.Y', $i)][$event->IdEvent] = $event->IdEvent;
// Event end date
//$this->_event_dates[date('d.m.Y', $event->EventEndDate)][$event->IdEvent] = $event->IdEvent;
