Islamabad is 5.5 hours behind Adelaide
Best overlap: 2:00 PM to 6:00 PM in Adelaide is 8:30 AM to 12:30 PM in Islamabad.
If you set up a recurring sync, 2:00 PM to 6:00 PM in Adelaide (8:30 AM to 12:30 PM in Islamabad) is the natural home for it. With 4 hours of overlap, 2:00 PM in Adelaide (8:30 AM in Islamabad) is a comfortable, repeatable slot for both sides. Remember that Adelaide shifts for daylight saving and Islamabad doesn't, so recalculate the overlap after each clock change.