This is out of the box with advanced outreach.  In the Participant Configuration you will find several things including


* Uniqueness criteria (when are two participants considered the same; would often be Case ID or something for this scenario it would usually be the Case ID, since that is the level at which the Advanced Outreach is operating)


* Exclusion List -- email addresses to exclude from the Advanced Outreach no matter what


* Advanced Criteria including the ability to declare a minimum number of days between an email address being contacted.  This is exactly intended for the use case you are referring to here.  Even if someone closes a case every day, we don't want to survey them more than once a week, or whatever.





Here is the documentation: https://support.gainsight.com/Product_Documentation/CoPilot_and_Automated_Email/Admin_Configuration/...


Look under "Criteria"

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By the way, you referred to PowerLists but don't forget that there are a whole variety of ways to add participants to an Advanced Outreach, not just through a PowerList.  You can use a Bionic Query (so the whole power of Bionic Rules to determine which are the participants!), a CSV or an *event* like case closure.     Really, this is totally set up to run a CSAT program.  Trigger the survey based on an event like Case closure, ensure that you don't send out multiple surveys for the same case, make sure that nobody is overloaded (as with your question) but also be able to send them reminders, etc. with very simple configuration.     One thing still ToDo is expiring the Surveys so that nobody accidentally answers an old survey (related to an older Case, for example) when they get a request related to a new one.  That is on the way. 

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