When non logged in users browse to a "Closed group" page
A very unattractive red Error message is displayed
I have changed the text and put a link to login in the INI File but I would prefer a login box and a nice image, or simply to redirect that user to already existing login page.
Check here
www.speakeasyenglish.org/club/groups/vie.../5-advertising-ideas

Anyway, this is what I have done for now, until of course you can give me an idea of a solution. Thank you
COM_COMMUNITY_GROUPS_UNLISTED_ERROR = "Sorry, you don't have permission to see this group Please<a href=" www.speakeasyenglish.org/club ">LOGIN</a> "

Hi
Sorry, there is no option to redirect page at this time. Because if a group has privacy for the logged in users too. from Jomsocial configuration > Privacy and Access control.
I will share it with development team, so if there is some option to customise it for you :)
UPDATE:
Kindly try this :
edit /components/com_community/views/groups/view.html.php around line 1263, find this code:

if ($group->approvals == '1' && !$isMine && !$isMember && !CFactory::getUser()->authorise('community.groupeditstate', 'com_community') && !CFactory::getUser()->authorise('community.groupedit', 'com_community') && !CFactory::getUser()->authorise('community.groupdelete', 'com_community')) { 
    $this->addWarning(JText::_('COM_COMMUNITY_GROUPS_PRIVATE_NOTICE')); 
}

if ($group->approvals == '1' && !$isMine && !$isMember && !CFactory::getUser()->authorise('community.groupeditstate', 'com_community') && !CFactory::getUser()->authorise('community.groupedit', 'com_community') && !CFactory::getUser()->authorise('community.groupdelete', 'com_community')) { 

    $mainframe = JFactory::getApplication(); 
    $mainframe->enqueueMessage(JText::_('COM_COMMUNITY_GROUPS_PRIVATE_NOTICE'), 'notice'); 
    $mainframe->redirect('index.php?option=com_community&view=frontpage'); 
}