I understand your point, and certainly that would be a way of applying a Band-Aid-type solution to the problem.
But, from what I have been told, the professional version of this simulation has most of the same characteristics that this version has. Certainly, if the military is actually using this simulation as a test platform, then it would drive them nuts if all of their HARM-armed units fired their missiles at a single radar unit, but failed to address the S-300 SAM battalion. That would be extremely unrealistic.
For simulation operational purposes, I would assume that the way that the professional version addresses this situation would be the same as how our version does. I assume this for two reasons. One, it's important; and two, because it's easier to have both version play in the same manner otherwise, as developers, you are constantly shifting back and forth. To not have them work in the same way would be somewhat ludicrous.
Thus, you would have to conclude that the professional version likely has the exact same issue as our version.
I have tried every method, sans Lua, to address this. The program will always address the radar-emitting target that it encounters first. The only way to "attempt" to get around it is to send another group of planes around the backside of the target area, so that the SAM is now the closest unit to them, and to delay their target off because you want the radar unit to be addressed first. Still, this method has some limitations, as well. The most important being, you aren't supposed to actually KNOW where the MOBILE SAM unit is before you launch your planes, because it could have moved.
Obviously, the whereabouts of a MOBILE SAM unit could (on does) change in real life. Hence, a SEAD PATROL (or SUPPORT) mission would be the logical choice to approach the situation. And, there may actually be times where it would be more advantageous to destroy the radar unit first, but not at the expense of never addressing the SAM (which usually has its own radar unit attached to it).
I believe that the best solution is to simply add another radar designation to the drop-down menu to further identify which type of radar (or the order of which) that you would desire to attack.