For the implementation, I think (attack the wing of my target) it could be a sort of derivation from the Attack Enemies. If "Attack the wing of my target" is ordered, then fighters would attack the ships in order that each ship would have the same number of attackers.
For "Protect the wing of my target", I don't know how it works, but I'm sure I already saw an order like that in one of the FSport or STR mission (when I was targetting an ally, his order was "protect alpha wing" for example).
For the command option... a touch sequence like "alt + 1" for attack the wing of my target would be too long to push. Imagine you want to give an order like that when you are dogfighting...
But I think the best solution could be to integer a submenu. Example : push C (command orders appears), then 3 "All fighters", then 1 "Destroy...", then 1 ".. my target", or 2 ".. the wing of my target"
And, for the user who doesn't want to destroy the wing of his target : the difference between C 3 1 and C 3 1 1 isn't so great. 50 ms or 100 ms maybe ?
But the negative point would be to modify some dialogs of the training missions. Or modify the order "Push C, 3, 1" by "Push C, 3, 1, 1"