Create email address with custom domain in WordPress Multisite

Hi,

I’m searching for a plugin like this for custom email addresses

http://en.blog.wordpress.com/2013/09/02/email-forwarding/

I copied some of the text:

Now, your custom domain is not just for your blog. Our new Email Forwarding feature lets you use your custom domain in your email address, so your email address can be just as memorable and unique as your blog. All your mail will be forwarded to the email address you choose.

I really appreciate any help you can provide.