Customize "RelateTo" parent in Meetings Edit view


I would like to limit the available options of parent “RelateTo” field in meetings edit view to the modules enabled for a specific user.
I created a custom view.edit.php and replaced

with the following

unset($this->ev->fieldDefs[‘parent_name’][‘options’][‘Contacts’]); //Remove Contacts
echo $this->ev->display($this->showTitle);

Although the “Contacts” option was removed, the “Add invitees” section disappeared.
Which is the best way to achieve this?

Thank you