Per administration it is possible to configure a preferred journal for documents submitted via the @to-zenvoices.com email address.
Via Manage / Environment / Administrations you can configure this per administration. Click the pencil icon to edit and then in the tab 'Preferences' select a default journal under 'Email submission'. Documents that are sent to the unique @to-zenvoices.com email address will then have this journal assigned as their destination.
It is also possible to change administration settings in bulk by selecting multiple administrations and then choosing 'Edit' via the bulk action.