Authenticate system user with alternate password

[AC]

Is there a way to configure Dovecot to authenticate a system user
against a different password list?  I want to give my own personal
account on my machine a password for IMAP and have that be different
from the password I use to log into the system for maintenance purposes.

I currently do this for outbound email by having the MTA authenticate
against a SASL database during the initial SMTP connection (STARTTLS).