Hello everyone

I'm trying to plan the RTW itinerary of my dreams and need some help. Starting in London, I want to include some African destinations (say Nairobi) in my trip.
However, considering that Nairobi is not connected to any OneWorld destination but London, I can't figure out how to get out of it without having 2 intercontinental departures in my orign (LHR), which is illegal.
The only option seems to be doing an awful surface segment to Harare or Jo'burg, which seem to be the only African destinations connected to continents others than Europe.
So, does that mean destinations like Nairobi or Accra are off-limits for itineraries starting in Europe unless you include surface segments to Harare/Jo'burg?
Or is there another way of doing something like London-Accra-London-Nairobi-London-...?

many thanks!

Claudia.