How to indicate that elective (not obligatory) subjects should be at the beginning or end of a day, and that compulsory lessons should have a strictly defined number per day

Our educational institution has compulsory and optional (elective) subjects. How to make optional subjects to be at the beginning and end of the day.

Compulsory subjects have strictly defined number: for lower classes there are no more than 5 lessons of compulsory subjects per day, for others – no more than six.

There could be several lessons of optional subjects before and after compulsory lessons.

Set that these subjects can be first and last, or first or last (as needed):

Set number of obligatory lessons per day:

Other way to set number of obligatory lessons per day:

Note: In this case, only lessons for full class will be counted. For example, if a group of one class has seven lessons per day of these compulsory subjects, the program will consider it as acceptable.

If you want to avoid windows between lessons in compulsory subjects, you can enter the following relationship: