What would be required to create the following scenario using Robo 9 tools?
I think that would be a feature request for RoboHelp 10.
On the basis that I have not seen anyone request this before, I somehow doubt Adobe would see any commercial justification. The search of what is running is the issue and that sounds more like something for your own developers. Then there might be a way of presenting just the right children from a merge, emphasise "might".
See www.grainge.org for RoboHelp and Authoring tips
Hi. Following up on Peter's good comments. This is definitely a "custom" engineered solution unique to your company. That said, if your developers want to pursue the feasibility, you should refer them to these online help topics so they can evaluate different approaches.
Point them specifically to the topic, "Information for Developers." Also note any item that mentions "WebHelp Pro or FlashHelp Pro" because that is the output produced and hosted by the RoboHelp Server.
Adobe Certified RoboHelp and Captivate Instructor