Not that I have seen. We use O365 for our exchange host so we have to have a local relay server with account credentials inputted that have access to other email accounts.
So for us, the email account italerts is logged into the relay server, and the account setup on the nimble is italerts. Since the relay server is logged in as italerts the relay server does the authentication.
You could also do the following
italerts account logged into the relay server, nimble alerts setup as the email account on the nimble box, but in O365 italerts has full access to send as the nimble email account therefor not needing a separate relay server for each account.
Hope that helps!