Custom email send address using Sites

Hi,

We are planning to deploy one more application B in to an existing portal which contains an application A . 

Both application A and B need to send external emails using different sender names 

Also at present email functionality in any shared portal has following limitations . I learned that it is due to cloud server configurations . I believe this can be resolved by using sites

1. You cannot change the sent from address or name. That means the emails will come from < Company Name > 
2. You cannot change email signature . We should always use one signature for all emails from a cloud server 

I believe this can be resolved by using sites . Can anyone who worked in sites , please confrm ?