Copy that. I have tried that however, if you have more than one “FAC Engage Group” it seems to ignore the the second one and go back to the “priority pattern” ou described. i.e. 1st is the first FAC Engage Group, next is a AAA, not the #2 FAC Engage Group.
I tried several ways of trying to “force” the AFAC to only use the several (usually 4) groups I wanted targeted, and it was getting really clunky. Today I take the opposite approach…give the AFAC an open-ended JFAC en route tasking order and keep everything don’t want targeted Invisible. We will see how that works.
In truth, I’m kind of bastardizing the DCS JTAC system to give it more of a JFACC CAOC directing the operation - not true CAS (in fact I don’t have any Blue Forces for many miles). Just a flight of jets with bombs and a Pred hanging out over the battle space vectoring them onto important, mobile targets like insurgents setting up a roadside IED, HVI traveling in a vehicle, maybe some WMD convoys. None of these ranks high in a the threat hierarchy (they are all just an unarmed vehicle and maybe a couple if insurgent infantry) but are the type of targets that UAVs are really good at tracking. So, for example, while there are some AAA or maybe armor down there, I’m really after “Carlos the Jackal” in that HUMVEE! 
Now that @Franze helped me with the Lua Predicate for detection of an enemy, I can generate relatively smarter SAM systems–really IADS–with the Options Alarm State and ROE. I start with all SAMs “Cold and Dark”- Alarm State Green and ROE Weapons Hold. I set up the Lua Predicate condition for a RADAR detection using an EW system or SR system that sets a Flag to On. Then use Time From Flag to first raise the SAM Alarm State to RED (radars on) in a couple minutes; ROE to Weapons Free a couple low minutes after that. Without getting into anything I might or might not know from my years “in the community” (or as @Franze likes to call it “Club Fed” 
), this does a pretty good job of replicating the decision process one might or might not see as an IADSs reacts to an air threat. All without (too much) scripting.
Now, as far as replicating realistic SAM engagement doctrine…i.e. shoot-look-shoot vs shoot-shoot-look, etc. Yeah, I’m thinking scripting is the only way to handle that.