We have some interns in our team and some people working with recurent activities, which causes them to have a avaliability lower then 8h/day. Is there a way to define diferent working hours for each users? Like, activities of 12 hours assigned for an intern that works 6h/day would be seen as 2 days, but if it would be assigned for a regular 8h/day workers would be 1d 4h. This would help us to set scrum Sprints more clearly.