While you can not send your Blast from multiple email address, if you want to make your Blast look like it was sent from two or more people, it is quite easy to do!
Depending on if your Instance has Sender Proxies toggled on or off, you will have different set of steps to follow. For more information about Sender Proxies, please review: Sender Proxies.
If Sender Proxies Are On
If your Instance has Sender Proxies toggled on, go to Blast > Controls to create a new Sender Proxy (also known as a Sender Profile).
At the bottom of the page, go to Sender Options > Available Senders, then click New Sender. Create a new Sender Profile with two or more sender names included in the Name field.
After you Add your new Sender Profile, click Save at the top right of the Controls page. The new Sender Profile will now be available in the Blast Editor's Sender Profile drop-down list inside the Sending Info section.
If Sender Proxies Are Off
If your Instance has Sender Proxies toggled Off, you can simply type multiple names in the Name field under the Sending Info section while in the Blast Editor.