Custom PrimaryKey Generation with autoincrement

Question

I need to define and generate primary key for 2 or more tables.

Tables hold same type of data but FOR Some BUSINESS RULES we have to make them separate say like

Answer 1

you could have a composite key over the zone id and auto id.

could also have a trigger that sets the pk to a custom string upon insert.

in general, would be best to keep these in the same table (since they have the same columns) and only differ by local vs. intl.