@Jeff 's suggestion will certainly work, but I’d recommend instead creating a Baseline, with the baseline relevance excluding your group. Then you can add the Adobe fixlet(s) to the baseline and use the Baseline action for deployment.
That will make it easier to swap in a new Adobe fixlet later and still have it excluded from this group.
Even better would be to resolve whatever problem you are having with those computers, and remove Adobe entirely. Not sure whether you mean Flash or Reader or something else, but both Flash and Reader are very common attack vectors now and you put your platform at great risk by not keeping them up to date; and at a serious risk by having them installed at all.