First you should have clients from Asia, Europe and NAM in different groups.
Create 3 liveupdate policies
1. Assign it to group with NAM clients it should say for liveupdate connet to default management server
2. Assign it to groups in Europe and it should have Europe's GUP configured in the policy and the clients will take defs from that particular GUP.
3. Assign it to groups in Asia and it should have Asia's GUP configured in the policy and the clients will take defs from that particular GUP.
or you can merge 2 and 3 and create a policy with multiple explicit GUPs and the clients will take defs accordingly.