Extract email addresses from the database, split in groups of maximum N (N<400) addresses, into JSON, email or CSV format (for mailchimp)
[
[{
"name": "",
"email": "",
"country": ""
}]
, [{...}]
]name1 <email1>,
name2 <email2>,
...
name1 email1 country1
name3 email2 country2