I don't get your problem, couldn't you store it like this: table timetable:

open | close | store 6am | 6am | default 7am | 12pm | store1

table stores: name | address store1 | xyx NYC

If you can't find the store in the timetable:

1. Get the timezone of the target store by looking up the address from the table stores

2. Set Hours from the default row in the timetable table on the object with the timezone