Hi, Dave. Yes, you'd just set them both up with the same user account. After you've set up the first car, add the 2nd car to your account by selecting "ADD A VEHICLE" from the main menu. You can only connect one user account with Alexa but it does support multiple cars on that account.
As a future feature request, it would be nice if the Alexa skill would respond to specific queries to individual cars. i.e. "Alexa, ask automatic where is my Prius?" It's frustrating to have to listen to a complete report on each vehicle when I only care about the one not sitting in my driveway.
Having written Alexa skills I know that words would need added for every make/model and this would be a pain, but it's not out of the realm of possibility. :-)
Just a suggestion - I do love the app! Keep up the good work.