Thanks, Zipper5. I considered using the solutions you suggested but neither one really fit the scenario I had in mind. Basically, I'm creating a mission where some VIPs pass by some friendly units...however, the units turn out to be, for lack of a better term, traitors. Therefore, I want the traitors' uniforms to be exactly the same as those of the regular Blufor units. I mean, if you're a US soldier protecting a dignitary and see an Takistani insurgent unit standing around in a crowd of US forces, it's pretty clear who to keep an eye on, eh?
That said, late this evening I found a pretty effective way of handling this situation. Basically, I'm using Blufor units (I'll refer to them as the main group) grouped to an Opfor unit whose probability of presence is zero. I keep these "main group" guys far away from the action. Meanwhile, I have matching Blufor units who act as placeholders for the real traitors. When it comes time for the traitors to reveal themselves, I...
1.) delete each of the placeholder units,
2.) teleport in the corresponding unit from the main group soldiers, and
3.) assign targets
...so that it looks as though some friendly units just went rogue.
I will prepare a small demo mission showing how I accomplished this in case others here might find it helpful as well.
Thanks again, though!