Preventive Maintenance Work Order Basic Dates Determination

Hi

I want to set the Preventive Maintenance Work Order Basic Dates interval to be determined from priority or to be manually entered somewhere in maintenance item. Is it possible and how?

At present to to provide interval between basic start and basic finish is calculated based on the task list operation duration.

How to enable the interval to be determined from prioriy or and any other way.

Thanks,

Panneer