Melbourne is 7 hours ahead of Addis Ababa
Best overlap: 8:00 AM to 11:00 AM in Addis Ababa is 3:00 PM to 6:00 PM in Melbourne.
Your shared working hours run 8:00 AM to 11:00 AM in Addis Ababa (3:00 PM to 6:00 PM in Melbourne). You've got a decent 3-hour window. Set a recurring time near 8:00 AM in Addis Ababa (3:00 PM in Melbourne) and stick to it. Watch the DST gap — when Melbourne changes its clocks and Addis Ababa stays the same, this window slides by an hour.