You may do the mass changing of the visibility via the MySQL command. First of all, choose any page and close the visibility option for the guests via Settings and remember the name of the page (it is placed in the page variable from the URL like studio/builder_page.php?type=bx_spaces&page=bx_spaces_create_profile).

Then go to your UNA database and run the following query (backup the `sys_objects_page` table first):

SELECT `visible_for_levels` FROM `sys_objects_page` WHERE `object`='[name of your page]';

Remember the appeared value and then run the new MySQL query:

UPDATE `sys_objects_page` SET `visible_for_levels`='[this remembered value form previous query]';