I'm trying to get this as an ability that can be managed at a squad-by-squad basis. And did you mean fighters can't buff themselves or squads can't buff themselves?
You can have a squadron's ability apply a buff that targets fighters, but you cannot have squads buff themselves (ApplyBuffToSelf). An example of the former:
this will apply the "BuffHeroicFighter" to all fighters in the gravity well. I'm assuming that you could also use "ApplyBuffToTargetsInRadius" and perhaps a few others without causing the game to crash, but don't quote me on that.
If "ApplyBuffToTargetsInRadius" also works, then you run into the issue that when attacking, fighters are never within X radius of the squadron center, so it would be impossible to apply a buff to only that squadron's members using "ApplyBuffToTargetsInRadius".
Unfortunately, I don't know of anyway to manage an ability on a squad-by-squad basis (but would be curious to hear if you figure it out).
Hope that helps.
edited for clarity