Howdy Benjamin,
Thanks for getting in touch and welcome to the forums!
I think there are two ways you could approach this.
The first is to use a plugin like Restrict Content. That plugin gives you a shortcode, which you could add to the Community Events submission form template.
Another way would be to add a conditional statement to the Community Events submission form template that checks whether a person is a logged in before displaying the content. Something like:
<?php
if ( is_user_logged_in() ) {
echo 'Sorry, you are not allowed to view this page.';
} else {
// The template code
}
?>
Does this make sense and will it help get you started? Please let me know. 🙂
Cheers!
Geoff