Not sure about ADD but a few years ago I flew Air Tanzania from Dar Es Salaam to Bujumbura - Burundi with a domestic stop at Kigoma:
During the chaotic check-in, where the last travellers of the queue could oddly pass first, there were two lines: one domestic one international, whom were attributed a different coloured BP according to the destination, green to Kigoma and a red to Bujumbura. Obviously one lane proceeded through the passport control, while the other lane on a separate way, had to go straight upstairs to the departure lounge.
It's only Inside the jetbridge that we met the Kigoma bound travellers who entered from the domestic area.