Let’s say that in CCB, you have a campus with a number of groups. CCB wants to keep track of the combined total number of people in those groups. To do this, the CCB software generates master system groups. The names of those groups begin with “All Members (of) <campus name>”.
You can sync a CCB master system group to MailChimp but you would not be able to sync that group from MC back to itself. It is not allowed by design and logic within the CCB software.
Within our application, we disable the option to select these groups when syncing FROM MC back to CCB, as nothing will happen if we allow you to sync. The CCB system will reject any changes.
The way this is done now is we search the groups whose names have “All Members of <Campus name>” in them and disable them from being selected (even though you can see them). So, to reiterate: while you can sync a CCB system group to MailChimp, you cannot sync back to it.
Pro tip: When naming groups, do not use the words “All Members” as in All Members of Campus A. Suggestions: Everyone in Campus A; Full Campus A; Entire Campus A; Complete Campus A; Total Campus A.
To sync all members of a campus, your best solution at the moment is to create a new group. First, run a search of the people you wish to include. Save the search report as a Saved Search. You can then directly sync that saved search and/or push the search results into a new group. This new group will be able to be synced from CCB to MailChimp and synced back from MailChimp to CCB.