despatch-new-event.php

<?php

// in your component

JPluginHelper::importPlugin('group');

$app = JFactory::getApplication();

$app->triggerEvent('onYourEventName', array($param1, $param2));


// in Plugin

class plgGroupYourplugin extends JPlugin
{
	public function onYourEventName($param1, $param2)
	{
		// Do some stuff
	}
}