Hi @kumarg - its not recommended by Adobe, but you can use multiple schedulers in your workflow and schedule the three different schedules separately.
Probably a better way to do it would be to have 3 separate "start" workflows and a main workflow. Each of the start workflows have a scheduler that executes on one of your schedules and some Javascript to fire an event call to kick off the "main" workflow which has an External Signal as the start point.
The Javascript in each scheduler would look something like
xtk.workflow.PostEvent("yourMainWorkflowInternalName", "signal", "",<variables />, false);
There are lots of ways to achieve this
Cheers
Darren