Zendesk Support Forwarding unworked tickets

I'm trying to create an automation that will automatically forward an idle ticket to a contractor. The problem is that I am currently the only agent, so tickets are automatically assigned to me. This prevents me from determining which tickets haven't been touched and which have based on assignment. I think I might be able to configure this with an SLA, but are there other options? I've got the notification target and everything else set up, I just can't determine which tickets have not been worked within the specified time frame.

Essentially, I'd like to have an automation that will take any new ticket that has not been worked and forward the details to an outside contractor. Help?