I'm long-time lurker coming out of the closet...

I am trying to understand whether what follows is considered back-to-back ticketing. I am based in ORD and in June have a business trip planned to JNB. This September-October, I would like to do a DONE4 and can stop in JNB as part of that trip. Can I purchase a round-trip ORD-JNB-ORD ticket, leaving in June and returning in October; and nestle inside that a DONE4, that would include at least one stop back in ORD? Or is this considered back-to-back ticketing?

In other words, the complete itinerary would look like:
ORD-LHR-JNB-LHR-ORD-....-SYD-JNB-LHR-ORD,
where ... indicates a few flights in North America. The first two flights and last two flights would be booked as a round-trip paid by my employer on AA/BA. The remaining flights would be the DONE4.

Given that the definition of an illegal ticket seems so vague, at least on aa.com, I'd like some assurance that this will not raise any red flags with AA or Oneworld.

Thanks, and thanks for all the helpful advice I've read over the years.
-R