hmm yes, you need to calculate the impact/explosion direction relative to the bricks,
lets say you have an explosion sprite, then you would create a angle test on all bricks relative to the explosion sprite
something like this
for each brick
brick.impactangle =
angle(explosion.x,explosion.y,brick.x,brick.y)
impulse at angle = brick.impactangle -180
for strength you can also do a distance check from explosion