Group Frequency Cap
Group frequency cap specifies how many times a single user sees ads from the any of the tactics in the group. By default, tactics deliver up to 3 ads every 12 hours. With a group-level cap, you can further limit the number of times ads appear.
For example, let's say you have a group that has two tactics showing similar ads. Tactic A and Tactic B each have frequency caps of 3 ads every 12 hours. The group frequency cap is also set to 3 ads every 12 hours.
If Tactic A delivers 2 ads and Tactic B delivers 1 ad to the same user within 12 hours, the group frequency cap applies, even though neither tactic frequency cap has been met yet. The user won't see another ad from the group's tactics until 12 hours have passed since the first impression.