When 'booking in groups' setting is chosen, each slot still asks for max number of students per slot, while it should be tied to groups instead. Otherwise teachers always need to have in mind how many students are in various groups, so all groups can be accepted by a slot. It would be nice to have this changed to respect groups, not individuals.

The crucial thing here is that groups can have different number of students, and you can never really limit a slot to a single group, i.e. there could be a group of 1 student than can fit in addition to another group.

Say, you have a slot with max 5 students. Group A is of 3 members, Group B is 2, and group C is 5. So, this slot can be taken by both Group A and Group B since they have 5 members in total.