If you don't mind the developers having access to your Google information, then you may want to explore these options: There are also some third-party add-on solutions.

Here are some examples of those SaaS solutions: If you're an organization doing a lot of targeted mailings and campaigns, you may want to consider uploading your email lists to an online service that will track campaigns and templates for you as well as give your users an easy way to unsubscribe.