Hi John,
You could use a template override (more on this in our Themer’s Guide) and wrap the calendar’s default-template.php template in a conditional that checks whether someone is logged in and either displays the calendar (for those logged in) or something else (for those not logged in). Something like this:
<?php
if ( is_user_logged_in() ) {
// The calendar markup
} else {
echo 'Please log in to see the calendar';
}
?>
I do want to note that we are fairly limited in how much we can support custom development questions like this, especially in our Pre-Sales forum here — but please let me know if you have any pre-sales-related questions and I’d be happy to help as best I can. 🙂
Cheers,
Geoff