IDE :: Use HitTestObject On All Instances Of A Movieclip

I'm trying to make a simple maze game. I have movement working, and now I'm trying to implement collision. Here's what I have:

An 8x8 grid, with walls of length 1 to break the grid up into a maze. the walls are instances of a movieclip I've named "mc_wall" a guitar-pick-shaped chip I'll control the movement of a cross-hair called "arms" that will check if there are walls immediately surrounding my chip by way of collision. "arms" is a movieclip made up of four individual movieclips: "uparm", "leftarm", "rightarm", and "downarm"

I have currently named each instance of "mc_wall" to be "wall" this is the code I have now (using only right as an example):

function moveRobot(event:KeyboardEvent):void
{
doslide = true;
if (event.keyCode == Keyboard.RIGHT)

[Code]....

this will work, causing the chip to remain in place if the rightarm detects "wall", and move if the rightarm does not detect "wall". My problem is that, although I have named every instance of "mc_wall" to be "wall", the only "wall" flash will recognize is the last one.

Is there a way to adjust this code to look at all 70-or-so instances of "mc_wall" instead of only the last one?