Do you need to consolidate all your domains into one and only have one mailbox to verify instead of 5 ? Domain Aliasing lets you do just that. Every e-mail account, alias or list that you create within your main domain will automatically be valid for all the define Alias Domains. 

Whenever someone e-mails joe@aliasdomain.com , the e-mail will be delivered to joe@maindomain.com and Joe only has to check one mailbox.