If you're talking about the "From" email address Intuit Link will use in its communication to clients, my understanding is that it's defaulted to the firm account's email address.  I don't believe you can choose to have a different email address just for Intuit Link for that purpose (although you can chose to use any email address when it comes to Client Activity Emails).

One workaround could be to be change your firm's email address to Gmail and then set yourself up (under your business email address) as an Admin.