Peer campaigns are groups of campaigns that stop the sending of one another.
How it works:
When a campaign with such a group is being sent, the time is saved and any other campaigns will not be sent within the specified time interval (in days).
Let’s say for example you have created campaign X and have Y,Z,W campaigns selected in the group, with a 7 days time interval:
After any of these campaigns is being sent (from all 4, including X), the rest won’t be sent if they match conditions within 7 days.