Melbourne is 16 hours ahead of Medellín
Best overlap: 4:00 PM to 6:00 PM in Medellín is 8:00 AM to 10:00 AM in Melbourne.
If you set up a recurring sync, 4:00 PM to 6:00 PM in Medellín (8:00 AM to 10:00 AM in Melbourne) is the natural home for it. With overlap this short — around 2 hours — a recurring slot at 4:00 PM in Medellín (8:00 AM in Melbourne) is worth its weight in gold. Heads up on dates: Melbourne will show the next day relative to Medellín when you meet. Because Melbourne and Medellín don't both observe daylight saving, plan to re-check the overlap around March and November.