Teacher cannot teach both in the morning and in the afternoon

You can use Main/Cardrelationships/Advanced and add Advanced cardrelationships:

Apply it to teachers - so that it is checked for each teacher indivdually and mark the the two timeoffs the corresponding periods.

You do not need to mark all the periods, if you for example leave the 6th period unchecked on both sides it will simply mean the software will ignore the lessons placed on 6th period when checking this rule. Then teacher can have 1-5 + 6 but not 1-5 + 7