So, certain characters possess powers/rules that allow them to improve the capabilities of those around them (ex: Vespid Strain Leaders, Guard commanders, etc) when part of a horde. Many times, it is advantageous for the PCs to eliminate these individuals to gain a better chance at victory.
How do you resolve this? Can your PCs single-out members of a horde? And if so, how do you balance that so that every combat doesn't begin with all of the enemy "horde commanders" getting sniped?