Newsletter unsubscribe using 3th party mailer

I want to use the newsletter list feature to manage subscribers of a list / newsletter that I send out. But I don’t want to use the erpnext native feature of sending messages because it doesn’t manage throttling of messages etc. It’s seems to be a very basic emailer currently without advanced features for list mailing.

The newsletter list feature in Erpnext is very usefull for managing subscribers. I would like to use the list so that people can (un)subscribe. I took al look at the unsubscribe link in the link (message) and noticed that in order to use it you have to have some kind of signature. So I am looking for a way to generate the signature / unsubscribe link for use in the external mailer. Is it possible to export the unsubscribe signature together with a list of subscribers (csv export)