Actually, I gave this some more thought, and if we treat the Computer Group as its base ‘bes fixlet’ type, we can query Web Reports through session relevance to get some interesting properties from the ‘bes fixlet results’ for the computer/group fixlet results.
‘relevant flag of it’ should show whether the computer is currently a member of the group. ‘first became relevant’ would be the first time the computer joined the group; ‘last became relevant’ is the most recent time the computer joined the group (if it’s been in-and-out of the group); and ‘last became nonrelevant’ is the most recent time a computer left the group.
This session relevance should show a report of all the group memberships. You can add filters on either the ‘bes computers’ or ‘bes fixlets’ to filter out the computers or computer groups in which you’re interested.
The ‘first became’ and ‘last became’ properties are only available in Web Reports, not in the Console Debugger, so you can run this in the Web Reports QNA page
q: (id of computer of it, name of computer of it | "Computername Not Reported", id of fixlet of it, name of fixlet of it, "Current Membership:", relevant flag of it, "First Joined:", first became relevant of it as string | "never", "Most Recently Joined:", last became relevant of it as string | "never", "Most Recently Left:", last became nonrelevant of it as string | "never") of (results (elements of item 0 of it, elements of item 1 of it)) of (set of bes fixlets whose (group flag of it), set of bes computers)
A: 10369450, WEBUI, 49, BigFix Infrastructure, Current Membership:, True, First Joined:, ( Fri, 24 Feb 2023 10:09:05 -0600 ), Most Recently Joined:, ( Fri, 24 Feb 2023 10:09:05 -0600 ), Most Recently Left:, never
A: 10369450, WEBUI, 50, Everything except BigFix, Current Membership:, False, First Joined:, ( Fri, 24 Feb 2023 10:09:05 -0600 ), Most Recently Joined:, ( Fri, 24 Feb 2023 10:09:05 -0600 ), Most Recently Left:, ( Fri, 24 Feb 2023 10:10:10 -0600 )
Here I have a host “WEBUI”, that joined the “BigFix Infrastructure” group on Fri, 24 Feb 2023 10:09:05 -0600 (when I installed the WebUI service on it); a few seconds later, at Fri, 24 Feb 2023 10:10:10 -0600, it left the “Everything except BigFix” computer group.
edit - brief note on using the hidden QNA page in Web Reports at REST API, Query, Relevance and three states