Limits a group of participants and generates automatically, when an user registers.
Example: Event date group with 10 slots, automatic allotment, participant group OU, number 2. If an user registers with the appropriate OU, an automatic allotment for the appropriate OU with number 2 will be generated. This automatic allotment limits the registration of 2 users with the appropriate OU. Thus a further user with the appropriate OU can register, too. Another user with another OU can register and generates a new automatic allotment. This will be done until the event date group is full, this means all slots are full.