The Professional Add-on has the feature ‘Custom fields with dynamic values’.
This allows you to add as many fields as you want with the possibility of adding values as variables which are replaced on the fly when the campaign is running. This allows you to add custom field values like permalink, image URLs, etc.
If you need more custom data, the plugin allows you to add a WordPress filter ‘wpem_meta_data’ to add names and values for custom fields.
Example:
add_filter('wpem_meta_data', 'my_custom_meta_data' ); function my_custom_meta_data ($currentmeta ){ $arraycf = array( 'mycf1' => $value1, 'my_cf2' => 1025 ); return array_merge($currentmeta, $arraycf) ; }
(not tested)
Also, keep in mind that all extra support for us to do something like this for you will require the premium support service.