Hi Francis, as far as i know Mifos Scheduler jobs are created to perform specific automated tasks at specified periods/intervals and they are bundled as part of the Fineract Platform. To create your own you have to get hands dirty a little on technical aspects of Fineract (Understand the architecture and database schema), as the scheduler jobs perform updates or even insertion into database tables.
The only thing you can modify in existing scheduler jobs is the interval/timing by providing your own custom Cron Expression.
I advise you pass it on as a request to the developer community and someone can catch it for implementation.
Regards
Stebbins