There isn't an option for that in 'Database -> Export Hands' but you can go to 'My Reports', create a 'Hand Report' and then filter for your last 100,000 hands by clicking the dropdown that says 'Most Recent 100 Hands' and selecting '<Specify Number of Hands...>'. When those hands have loaded select all hands in the report using CTRL-A then right-click on the report and select 'Export Original Hand Histories'.