Allow dancers to register for partial class

We occasionally have dancers who will only take 1 day/week (instead of 2) for a scheduled class. There are 2 ways we have tried to manage this: scheduling the class as 1 day/week for each day and dancers who take both days register for both OR schedule the class as 2 days/week and add absences for the dancers that do not attend every day. The first method was very confusing for parents and the second was a lot of work to schedule out a season full of absences for those dancers. It would be great to have an option to indicate which days each dancer is attending and to set a partial tuition amount for that class.