Duryodhana is factually telling Dronacarya that although Bhishmadeva is partial to the Pandavas, the Kaurava victory is dependent on the vigilant protection of Bhishmadeva. So he must be protected from all sides in such a way that he cannot be slain form any direction. The Kaurava army depends solely on the might of Bhishmadeva.

Madhvacarya has no commentary so we present Baladeva Vidyabhusana's.

If Drona becomes indifferent understanding the implications of negligence hidden in these words my purposes will be hampered. Thinking this Duryodhana assured him of his confidence in his ability by the use of the word ayanesu indicating prowess. You all being divisioned at strategic points in your various military formations should not leave your positions for you all must carefully protect Bhishma from both sides and behind as he will be so engaged in the overall battle he may not be aware of his immeadiate surroundings. If he is protected properly then our victory is assured. Duryodhana's intimation was that Bhishma is my grandfather and Drona is my preceptor thus both must be my well-wisher and this was already proven in the royal assembly during the game of dice with the Pandava's when neither Bhishma or Drona responded to the overt indiscretions against Draupadi; even though they both could see the injustice and transgression that she was subjected to by Duryodhana.

So Duryodhana faced with the feeling of inadequacy reflects what is to be done? In this verse he replies that all of his army situated in their respective strategic points in their various positions must support and protect Bhishma very carefully, who is the commander of the army. It is understood that where the commander is protected the army is protected.