“It is not unusual for joists to lap or butt in the middle of a span rather than build across a platform. When they do, they typically bear on a wall or beam at that point. To produce joists that break over a support, specify the wall or beam in question as Bearing in its specification dialog:
• Check Bearing Wall in the Wall Specification dialog. See Structure Panel on page 264.
• Check Bearing Beam in the Framing Specification dialog. See General Panel on page 637.”
There are a few more references. These are also present in the in-program help system.
Technical support replied to my case and said this feature is only present in Chief Architect, not in Home Designer and the documentation is an error or was overlooked.
I’ll mark this as “solved”. DJP was correct that it can’t be done. But you can see the confusion because the documentation says it can…
Confusion resolved. Hopefully they’ll update the documentation and in-program help system to prevent future confusion.
RMR-Ethan's post in Designating Interior Wall as Load Bearing was marked as the answer