Help with filter: Updated by != member of Assignment Group

[JP-ODU]

I'm having a hard time with what I expected to be a straightforward filter: the request is to list only those Incidents that have been last updated by a user who is not a member of the incident's assignment group.

The first part is easy: Updated by | is not

The challenge I'm having a hard time wrapping my head around is how to correctly express the "member of the incident assignment group" in the filter. Any ideas?

Thanks!

[JP-ODU]

Thanks LMeats, that would be very handy! I'm not able to find the script includes "new Arm_groupUtils" is it possible that's unique to your instance? Could you share the script from there?

[JP-ODU]

I also found this (https://community.servicenow.com/community?id=community_question&sys_id=335b0b21db9cdbc01dcaf3231f9619e3) 8 year old discussion but:

(1) the solution isn't quite what I'd hope for, it uses the logic "is not a member of my/current user's assignment group" and I'd really to be able to filter for "updated by | is not | a member of the assignment group on the ticket"

(2) I can't seem to make it work, in general? When it comes time to enter "javascript:getMyGroupMembers()" into the filter, it just turns "(empty)"

I'm really open to any approach for filtering incidents to show updated by | is not | member of current assignment group. Has anyone found a way to script this, effectively?