Solution:
You can use wpcf7_before_send_mail
action hook to prevent form being sent to email.. (I have tested this with “Contact Form DB” plugin – it saves data before email is filtered)
To filter only specific Form IDs – use something like this:
function wpcf7_skip_email_sending($wpcf7_data)
{
if ( in_array($wpcf7_data->id(), array(2,3,7)) ) {
$wpcf7_data->skip_mail = true;
}
}
add_action("wpcf7_before_send_mail", "wpcf7_skip_email_sending");
(For older CF7 version you might have to change $wpcf7_data->id()
to $wpcf7_data->id
)