I’m not sure I understand. Is this a technical problem with bb or a conceptual problem with your idea?
If you make fake accounts so you can post threads with the right dude’s name, and the right dude turns up later, just give him your fake account. That’s not automatable by default, you would have to manually edit the profile to set their email and then let them set their own password. But it would work.
Do you have the right dude’s permission to post his jobs?