@Lurie there's no way to do this automatically without using the API.
Butler is a good choice for this, but as Trello just acquired Butler they're currently working on integrating it and not accepting new users.
I built a free/open source API tool called Trellinator that allows this type of thing to be done relatively easily using the Trello API executed by Google Apps Script:
Hi, team, Whether you've been hanging out here in the Trello collection for awhile, or whether you're just now joining us from the Trello Slack Community, we’ve got some exciting news about th...
Connect with like-minded Atlassian users at free events near you!Find an event
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no Community Events near you at the moment.Host an event
You're one step closer to meeting fellow Atlassian users at your local event. Learn more about Community Events