Special Rules: Lance,Shield and Sword: As long as they are within 3" of another Knight from this formation. Knights from this formation can re-roll failed saves for there ion shields. Furthermore, as long they begin the assault phase within 3" of another Knight from this formation. Knights from this formation can re-roll their charge distances, and inflict D3 Hammer of Wrath hits when they charge.
I read this as meaning all 3 Knights dont have to be in range of each other, just 2 of them for the bonuses to take effect. Of course it would only effect the 2 Knights within 3" of each other. The third would not. This also allows the bonuses to still be in effect if you lose a knight as well.
Also re-rolls on the charge. Can you choose to re-roll only 1 die for the charge distance or do you have to re-roll both ? So in the example i roll a

and a

i want to keep the

and re-roll the

. Is this allowed ?