Need to update account record based on country in Salesforce

Hi Experts,

I have requirement where I need to update accounts by running batch class based on country values eg: I have 10 account records in that 4 belongs to America, 6 belongs to Japan, now to update 4 American account record I need to run my scedhular in American time zone same way for Japan, here I am not getting how do I run my scheduler and update record based on county. In my account there is field called sales country in this field only country will populate. Kindly help me