Ok, that is what I was thinking was going on.
It strikes me then you are then limited to one group called “true” and you can never user that “confirmation” approach again.
I will run with the drop down for now as I might want to change the group filter on say an annual basis, i.e. a group for each year.
Finally, if I can suggest to the makers of the automation, to perhaps consider a more explicit step and thus field, to specify the intended user group that is the target of your filter, as this implied part of the setup has caused me a lot of confusion and time as it probably as others.
Thank for all your help and exposé @Moin