On the fly you can select to email to either Bill-to, Ship-to or Customer.

The Bill-to or Ship-to will be those on the quote, which you can onetime override.

You can add multiple email addresses to a single email field separated with a "," but unless the domain name is really short I've found that he maximum you can include is only two, one if the domain name is really long.

There isn't any good way to email a quote to multiple recipients other than one at a time. If you are storing the email address in a Ship-to then you would have to create the quote with the first Ship-to that you want to send the email to, then email the quote, then edit the quote to change the ship-to to the second recipient, send that email, etc until you have sent them all.

Unless the recipient list is always the same, there isn't even a great way to do this with my favorite "solve all printing problems" solution, PrintBoss.