Teach different days without repeating the course

[remi]

The teachers at my institution have up to three subjects in the same course, so how do I ensure they don't teach on the same day as the other subjects in the course? In other words, how can I arrange for them to teach on different days without repeating the course?

[Liviu Lalescu]

Sorry, but I don't understand. Could you show an example?

[Volker Dirr]

I guess he mean something like this:
Teacher ABC has got:
4 hours math in Group 10a
2 hours physics in Group 10a
2 hours chemistry in Group 10a
and he want only 2 of that activities per day. Not 3.

It is a but depending on your exact data set.
You could tag that activities and allow max 2 hours per day. This is in fact the exact way.

But I prefer a bit a more strict variant:
In that example a min n day constraint (100% weight) with the physics and chemistry activities will be maybe better (so just modify the already existing physics or chemistry constraint).

[Liviu Lalescu]

In this case, Volker, maybe also teacher(s)/students (set) max activity tags per day from set.