Can anyone provide information on setting up a newsletter emailing system within an existing Laravel website?

I'm taking over the development and maintenance of a web-application built using Laravel 5. The current application includes a user management system where users can sign up, be assigned roles by our admins, and get access to different aspects of application and website depending on the permissions given to them.

What we now need is a way to send mass emails / newsletters to some subset of these users (and potentially other email address that have subscribed to our website but haven't registered as users). This needs to include a front-end where registered users (with the appropriate permissions) can create the emails / newsletters, manage their subscriptions to the different mailing lists, and some kind of administrative dashboard.

Would anyone be able to point me in the right direction to either

1. Existing solutions that can be integrated into an existing user-management system, or
2. Commercial services that can develop such systems Thanks!