We only need to modify the "Cover" behavior to accept the positioning "attitude" as a parameter. Then, when calculating the target position, we simply use the grid tool to shift the sector up or down rows in proportion to the attitude value.
So here's an example of the defending teams "covering" positions with two different attitudes. One to sit back more and one to press higher up.
Here the defensive line drops off and sits deep, closer to their own goal.
Here the defensive line press higher up the pitch.